yacht battery

• Pontoon Boats
• Personal Watercraft
• nauticalknowhow
• Nautical Knots
• Tools and Calculators

Reviewing The Best Marine Batteries of 2024

Odyssey 31-PC2150S Heavy Duty Commercial Battery

Banshee LiFeP04 Deep Cycle Battery 100Ah 12V

Bass Pro Shops Pro Series Deep-Cycle AGM Marine Battery

Getting the best marine battery for your boat is the key to having a successful outing, whether you are fishing, sailing, or boating. The device might not be as huge as some other components of a boat, but you can be sure your battery-powered boat isn’t moving an inch without it unless you resort to paddling.

A marine battery doesn’t only start your boat’s engine . It also powers all onboard appliances.

It would seem like an easy thing to choose a marine battery considering the vital role it plays in a boat, but that’s always the case. You’re probably reading this article because you are faced with the seemingly difficult task of picking a suitable battery for your boat. We’ve rounded up some of the best options, as you’ll find out.

Best Marine Battery – Reviews

Odyssey might be a relatively new energy solutions company, but it has established itself as a force to reckon with when it comes to rugged, long-lasting equipment. There is a reason the Odyssey 31-PC2150S battery is called an extreme battery. That’s because it is specifically designed to meet the demands of heavy-duty vehicles from farming equipment, tractor-trailers, boats, and more.

This battery has enough power to start many powerboats without breaking a sweat, and its rugged construction protects it against vibration and impacts that can easily damage other batteries. It is fitted with pure virgin lead plates for maximum conductivity and power. The brass terminals are tin-plated and corrosion-resistant.

Specs and Features

• 100 amps, 12 volts
• 1150 cold crank amp
• Weighs 77.8 lbs
• Retains stable voltage for long periods
• 70% longer cycler life compared to many traditional deep cycle batteries (up to 400 cycles)
• Fast recharge (up to 100% recharge in 6 hours or less)
• Non-spillable design for flexible mount
• Vibration resistance
• – 40 o F to 113 o F operating temperatures
• 4-year full replacement warranty, 3-year limited warranty
• Buy on Amazon   →
• Buy on Walmart   →

Banshee did not exaggerate when it described this Lithium-ion LifePo4 battery as a super lightweight and long-lasting model. The deep cycle battery weighs 60% less than any typical lead battery and lasts up to three times longer than most SLA or AGM batteries.

Dual terminal marine posts effectively eliminate the need for adapters. Just in case the battery runs down for any reason, the emergency start function will get the juices flowing again.

Specs and Features:

• 100 amp hours, 12 volts
• Lightweight battery compared to other similar marine batteries (weighs only 24.2 lbs)
• Built-in LED voltage indicator tells you the battery voltage
• High power battery management system (BMS) to keep the battery from over-charging, excessive discharge, and short-circuiting
• Emergency start button (only activated when the battery is depleted)
• Dual marine posts
• Low self-discharge allows it to start after long periods in storage
• Green energy battery (non-toxic and does not contain lead)
• Up to 70% more cranking power
• Carrying handle
• 3-year warranty

Optima YellowTopD27F Dual Purpose Battery

We recommend the Optima YellowTop D27F Dual Purpose battery for boaters who want to install heavy electrical appliances in their boats. It is powerful enough to crank up the engines and also power demanding electrical accessories, including inverters, audio systems, winches, and more.

This option outperforms other traditional batteries when it comes to cranking power. In addition to faster-charging capability, the model has three times the cycling ability of most conventional batteries.

YellowTop D27F comes in a durable polypropylene case that is designed with durability in mind. It is completely spill-proof and mounts in virtually any position. Plus, it can handle vibration way more than most other models.

• 66 amp hour, 12 volts
• 830 Cold cranking amp
• 1026 cranking amp
• Weighs 54 lbs
• Spill-proof
• Can be mounted in all positions
• Over 300 recharge and discharge cycles
• Excellent vibration resistance
• Faster charging and maintenance-free

$371.48 Amazon  →

Only a few small to medium marine batteries combine a reasonable retail price with outstanding performance the way the Pro Series Deep-Cycle Marine Battery does. Bass Pros Shops packed quite some power into this model, with outstanding cold-cranking amps, reserve capacity, and marine-cranking amps, so you don’t need to load up on batteries.

It starts up your engines, and the deep-cycling function quickly kicks in to power your trolling motor and any other onboard appliance, including audio systems and fishfinder. The battery recharges very fast and can withstand lots of deep discharges.

Installing the battery is quite easy due to the dual terminal design, and you can be sure of long-term use because the AGM construction is engineered to resist shock and vibration.

• Weighs 56 lbs
• 545 Cold cranking amp, 25 amps (120 minutes) reserve capacity
• Hybrid engineering for dual-purpose use (cranking and deep cycle)
• Top-of-the-line vibration resistance
• Impact-resistant
• 0 to 12 months free replacement warranty, 13 to 36 months pro-rated warranty

$174.99 Bass Pro  →

Mighty Max ML35-12 - 12V 35AH Deep Cycle Battery 

The Mighty Max ML35-12 – 12V 35AH Deep Cycle Battery is proof that buying the best marine battery doesn’t necessarily leave a dent in your wallet. It is constructed with small trolling motors in mind and works well for small kayaks, canoes, and boats.

It might be very affordable, but it comes with the remarkable benefits of AGM construction, including maintenance-free and leakproof. Mounting can be done in almost any position, so it can fit in lots of tight spaces and around accessories.

• 35 amps, 12 volts
• Weighs 23.15 lbs
• Sealed Lead Acid (SLA) and Absorbent Glass Mat (AGM) chemistry
• Wide operating temperatures
• Impressive performance in low and high temperatures
• High discharge rate with deep discharge recover
• 30-day refund policy, 1-year warranty

VMAX SLR125 AGM Sealed Deep Cycle 12V 125Ah Batteries 

Adding more appliances to your boat may mean upping your battery power, and sometimes more output power means buying two separate batteries. If you ever find yourself in that situation, you may want to consider the VMAXSLR125 AGM Sealed Deep Cycle batteries.

These are not the typical marine batteries that die out after a couple of years. These batteries can deliver exceptional performance for up to 10 years in float mode. The twin-device is backed by a 12-month warranty policy.

• 125 amp hours, 12 volts
• Two deep cycle batteries (sealed)
• Weighs 75 lbs
• Between 8 and 10 years float mode lifespan
• VMAX BC1215 12V 15Amp 7-stage charger recommended
• Designed for 99% recombination capabilities
• Safe for use, does not contain dangerous gases or fumes
• 1-year warranty

XS Power D6500 XS Series 12V 3,900 Amp

When it comes to the best marine battery for boat racing, the XS Power D6500 takes the lead. It is one of the AGM batteries that use the highest energy density chemistry. You can mount this model in almost any position, and because it is both spill-proof and vibration-resistance, you can be sure of an extended lifespan.

• 75 amp hour, 12 volts
• Weighs 58.3 lbs
• Vibration-resistant, ultra-low internal resistance
• Comes with M6 terminal bolt
• Mounts in nearly all positions
• Sealed, valve-regulated
• Suspended electrolyte in fiberglass

Optima 34M BlueTop Marine Starting Battery

Shopping for a medium power cranking battery? You may want to consider buying the Optima 34M BlueTop Marine Starting Battery. This is an excellent choice for people who want to be absolutely sure that their boats will start no matter what.

You can rely on the Optima 34M BlueTop for cranking power, even in terrible weather conditions. A tightly wound construction ensures the plate movement is kept very low, with great vibration resistance. It also comes with a high reserve capacity for longer shelf-life. That means, even when your boat is not in use, you can be sure it will crank up easily with this marine starting battery.

The brand’s unique SpiralCell design offers clean power, making the battery safe for the environment.

• 800 cold-cranking amps, 12 volts
• 100 minutes reserve capacity
• Weighs 36.4 lbs
• Optimal starting power regardless of the weather
• Versatile use (for boats and RV)
• Maintenance-free

Marine Battery: Types and Maintenance Tips

It goes without saying that marine batteries are specifically meant for use on boats, making them more expensive than their automobile counterparts. These batteries are engineered with more robust designs to withstand the hard knocks that occur in boats.

It is never a wise decision to use a car battery on your powerboat. Even if it succeeds to power the engine, it is only a matter of time before it crashes under the heavy vibrations and demands of a boat.

Types of Marine Battery

Marine batteries fall into three broad categories, namely:

• Marine Starting Battery : As the name suggests, this battery type is designed to start the boat’s engine, providing quick bursts of power. The onboard alternator rapidly recharges the battery. If you ever need to power your appliances or troll motors, you should do so with another type of battery, as starting batteries are not suitable for these purposes.
• Marine Deep Cycle Battery : This is the ideal battery for powering onboard accessories, including fish locators, windlass, audio systems, thruster, depth finders, and more. The device is designed to discharge slowly over a long period. It goes through hundreds of charging and discharging cycles. Avoid using a deep cycle battery to power your boat’s engine.
• Marine Dual-Purpose Battery : Having one battery onboard for starting your boat and another for powering your appliances can take up space. A space-saving solution is a dual-purpose battery that combines the performance of deep cycle and starting batteries. Keep in mind, though, a typical dual-purpose battery will not provide the top-notch performance of either starting or deep cycling batteries separately.

Charging a Boat’s Battery

Unlike cars that are used almost daily, boats are less likely to be on the waterways every day of the year. This explains why an automobile battery tends to last longer in cars than even the best marine battery in a boat.

If you have to leave your boat in storage for a while, it is important to make sure the battery retains its charge. Trickle charging or regulated charging is recommended when the boat will be out of use for a long period.

Also, remember to properly charge the battery in a boat you just purchased, whether it is a new or used boat. The batteries that come with a new boat will typically lose most of their charge while in storage.

If you’ve had a battery for a while, and it suddenly goes dead when you go to start it one morning and will only come to life when you plug in the charger, you may need to start preparing to replace the battery.

Replacing the Battery

When it comes time to get a new marine battery, make sure to buy a new one that works for your boat. A good place to start is looking through your boat’s owner’s manual or consulting a marine dealer to find out the option for your specific boat. You need to pay attention to the battery ratings, including marine cranking amps, amp hour rating, and reserve capacity.

If you need to replace a starting battery, you should take particular note of the marine cranking amps and make sure it matches your boat’s engine specifications. If you are in the market for a deep cycle battery, your primary focus should be on the reverse capacity and amp hour rating. Shopping for a dual-purpose replacement battery will mean looking out for all three rankings.

Getting a replacement battery is not limited to only when you end up with a dead one. If you consider adding new electrical accessories to your boat, it is vital to upgrade to a model with an adequate ampere-hour rating. This is particularly important if you use your audio system a lot while your boat anchor is down or if you troll with the engine running at low speed.

Tips for Preventing Battery Problems

Marine batteries may not be particularly classified as very expensive, but no one enjoys shopping for a new one ever so often. However, even the best marine battery will develop problems if not properly maintained. Here are some easy-to-follow suggestions to keep your battery running smoothly and extend its life expectancy.

• While it may not be possible to use a boat every day, it is important to get it out in the water and give the electrical system some good exercise. This is one of the simplest ways to make sure your marine battery lasts for a long time.
• A maintenance-type charger is ideal for keeping the battery fully charged when you are not using the boat. Consider getting this type of charger if you use your boat once in a blue moon.
• You want to fully charge your marine battery before storing your boat for the off-season. Make sure to disconnect both terminals so that nothing drains the battery while in storage.
• Keep the battery secured with a tray specifically for that purpose. The tray should be tightly screwed to the boat with a locking strap to keep it in place. This should prevent it from coming loose as the boat vibrates in rough waters.
• Develop a routine of frequently checking the terminal connections. While a good battery try can keep the battery in place, wear and tear often happen with all the vibration and banging around on the water. Ensure the terminals are tightly connected and free of corrosion.
• Make sure the positive terminal of the battery is covered. If it is not, install a cover, regardless of whether the battery is inside a covered box. A terminal cover is your surest bet to prevent arcing, sparks, and possible explosion (a tool dropped on the terminal can cause an explosion in some cases).

My grandfather first took me fishing when I was too young to actually hold up a rod on my own. As an avid camper, hiker, and nature enthusiast I'm always looking for a new adventure.

Categories : Boats

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

More in Boats

What Is A Gunwale?

131 of the Best Hawaiian Boat Names

167 Patriotic Boat Names

The 138 Best Boat Names for Dog Lovers

The People’s Poncho Review and Ratings 

Oru Lake Kayak Review

About Boatsafe

Established in 1998, BoatSafe is your independent guide into the world of boating, fishing, and watersports. We provide expert insights and detailed guides to help you find products tailored to your needs and budget.

Contact Boatsafe

• Address: 4021 West Walnut Street. Rogers, AR 72756
• Phone:  (479)339-4795
• Email: [email protected]

Site Navigation

• How We Test
• Corrections Policy
• Privacy Policy
• Terms & Conditions
• Editorial Policy
• Affiliate Disclosure

Our Reviews

All content is © Copyright 2024. All rights reserved.

Boat Reviews

• Boats Specs
• Marine Pros
• Boat Insurance
• Boat Warranties
• Boat Transport
• Boat Towing
• Marine Forecasts

Your Ultimate Boating Resource

Marine Battery Essentials: What You Need to Know

The marine battery is an essential component of any boat’s electrical system, providing power to a variety of items including navigation equipment, lighting, and engine starting. It’s crucial to understand the basics of marine battery selection, installation, and maintenance to ensure reliable, safe, and efficient operation of your boat’s electrical systems. This article will guide you through marine battery essentials and address what you need to know.

Types of Marine Batteries

There are three main types of marine batteries: starting batteries, deep-cycle batteries, and dual-purpose batteries.

Starting Batteries

These batteries are designed to deliver a high burst of current to start the boat’s engine. They have a large number of thin lead plates that enable them to discharge high currents quickly. However, they are not suitable for powering electrical devices for extended periods.

Deep-Cycle Batteries

Deep-cycle batteries are designed to provide a steady amount of current over a long duration. They have thicker lead plates, allowing them to be discharged and recharged repeatedly without causing damage. Deep-cycle batteries are ideal for powering electrical devices like trolling motors, equipment, and appliances on board.

Dual-Purpose Batteries

As the name suggests, dual-purpose batteries combine the functions of starting and deep-cycle batteries. They can provide the high current needed for engine starting while also supplying power for electrical devices on board. Although they may not perform as well as dedicated starting or deep-cycle batteries, they offer a convenient, all-in-one solution for boaters with limited battery storage space.

Marine Battery Size and Capacity

Marine batteries come in various sizes and capacities to accommodate different types of boats and electrical load requirements.

Battery Group Size

The battery group size is a standardized classification system that indicates the physical dimensions of the battery. Common marine battery group sizes include 24, 27, and 31. The appropriate group size will depend on your boat’s battery compartment size and the specific battery manufacturer’s recommendations.

Ampere-Hour (Ah) Rating

The capacity of a marine battery is measured in ampere-hours (Ah), which signifies the amount of current the battery can supply for an hour before being completely discharged. A higher Ah rating indicates a larger battery capacity, which can power more electrical devices or last longer under the same load. When choosing a marine battery, it’s essential to consider your boat’s electrical demand and select a battery with adequate capacity to supply the required power.

Battery Maintenance and Safety

Proper maintenance and safety precautions are necessary to ensure optimum battery performance, extend service life, and avoid potential hazards.

Periodic Inspection and Cleaning

Regularly inspect your marine battery for any signs of damage, leakage, or corrosion around the terminals. Keep the battery clean by wiping it down with a damp cloth and removing any dirt or deposits on the terminals. To prevent corrosion, it’s recommended to apply a thin layer of dielectric grease or petroleum jelly to the terminals after cleaning.

Charging and Maintaining Proper Water Levels

Regularly charging your battery will help it last longer and perform better. Use a quality marine battery charger designed for your specific type of battery to ensure safe and efficient charging. If you have a flooded lead-acid battery, it’s essential to maintain the proper electrolyte levels by adding distilled water as needed. Be sure to follow the manufacturer’s specific instructions regarding charging and electrolyte maintenance.

Safe Battery Storage and Ventilation

Make sure to store your marine battery securely in a well-ventilated battery box or compartment on your boat. This will protect the battery from physical damage, moisture, and excessive heat, which can all contribute to decreased battery performance and service life.

Follow Manufacturer’s Recommendations

Always refer to your marine battery manufacturer’s recommendations for installation, charging, maintenance, and safety precautions. Adhering to these guidelines will ensure maximum battery performance, longevity, and safety on board.

Understanding the essentials of marine batteries is crucial for any boat owner. By selecting the right type and size of battery, ensuring proper installation and maintenance, and prioritizing safety, you can optimize the performance and lifespan of your marine battery, providing your boat with reliable power for all of your on-the-water adventures.

RELATED ARTICLES

Overview of the 2024 sea-doo rxp-x 325, overview of the 2024 parker offshore 2900 cc, what your boat’s beam is and why it matters, power cats of 2024: ultimate guide to the top power catamarans this year, navigating the heat: 10 safety tips for a safe boat ride in the summer heat, latest posts, don't miss, our newsletter.

Get the latest boating tips, fishing resources and featured products in your email from BoatingWorld.com!

What type of wood is used for pier pilings?

What is the difference between a dock and a floating pier, what is the proper technique for pulling a beginner wakeboarder, what does ‘no wake’ mean on a lake, what is the difference between wash and wake, highs, lows, and tidal know-how: a deep dive into ocean currents, 10 essential tips for fishing near private property, the benefits of using a drift sock: guidance for anglers, lure fishing: secrets for imitating live bait and attracting fish, explore the untapped depths of america’s best bass fishing spots, outboard motor maintenance: tips for keeping your engine in top shape, the essential boat tool kit: tools every boater needs, diy boat building: 8 tips and tricks for building your own vessel, the art of miniature maritime craftsmanship: ship in a bottle, antifouling paints: a guide to keeping your boat shipshape, beginner’s guide to standup paddle boarding: tips and techniques, boating for fitness: how to stay active on the water, kayak safety: how to stay safe on the water, anchoring in a kayak or canoe: how to secure your small boat, overview of the 2024 yamaha 252sd, overview of the 2024 tiara yachts 48 le, overview of the 2024 bass cat jaguar sts, 2024 pursuit os 445: an overview, 2024 aquila 47 molokai review, 2024 sea-doo switch 13 sport review, gear reviews, megabass oneten max lbo jerkbait review, fortress anchors fx-7 anchoring system review, fortress anchors fx-11 anchoring system review, fortress anchors commando anchor kit review, fortress anchors aluminum anchors review, stay in touch.

To be updated with all the latest news, offers and special announcements.

• Privacy Policy

• Yachting Monthly
• Digital edition

How to improve power management on a yacht

• August 21, 2024

Mike Morgan offers advice on how to improve power management on a yacht and preserve precious amps for those that like their home comforts

I confess, I’m not a marine electrician, and my understanding of boat electronics is at best rudimentary, but I’ve now been managing my boat’s power generation and consumption for three seasons and have developed an approach which seems to work well. Hopefully, you will find some of the following advice useful when it comes to managing your own yacht’s energy needs.

Every boat has its own particular balance of power generation and demand, so my system may not work perfectly for you, but it might help you start managing your precious amps a lot more effectively.

My wife Debbie and I sail up to nine months a year around the Med, predominantly lying at anchor. We avoid marinas and use our generator infrequently, to help save the planet and our budget.

I won’t address power needs whilst under sail here, as it’s not relevant to our cruising profile. Clearly, if you’re taking on an Atlantic crossing , then you’ll need to consider the power demands from your navigation equipment, lights and auto pilot.

We bought our pride and joy, Spirit, a Bavaria C57, brand new in 2021, and made several upgrades in an attempt to achieve the holy grail of self-sufficiency at anchor. We opted for 800 amp hours (Ah) hours provided by lithium batteries that weigh less than a single 150Ah lead acid battery.

Because lithium offers roughly twice the capacity of lead acid, that’s equivalent to 16 100Ah lead acid batteries with a combined weight of just over a third of a ton. Given Spirit’s generous beam, we’ve been able to accommodate four 420W solar panels, giving a potential maximum of 1,680W.

A few of the electrical galley appliances aboard Mike’s Bavaria C57 and the wattages that similar products might draw off your battery if you have an inverter

State of charge

The amount of electrical power you have available is all about batteries. Boat batteries are usually measured in amp hours (Ah) – the total number of amps devoured in one hour of use. So, a 120Ah battery will, theoretically, deliver 120A for one hour or 1A for 120 hours. But, of course, this is a little simplistic.

If you have lead acid batteries, you must never completely discharge them, unless you want to replace them regularly. Lead acid batteries should never be discharged below 50 per cent, so the practical Ah they really offer is half the theoretical Ah rating. In the above example, 60 hours at 1 amp would be the limit before you had to recharge the battery. Typically, the state of a battery’s charge is monitored by volts or a shunt battery monitor.

Knowing the state of charge of your batteries is critical to managing your power needs.

Article continues below…

How to get your yacht home without power

Electrical systems and electronics have become such an essential part of our normal lives that it’s hard to imagine life…

Everything you need to know about yacht solar power

Keeping your batteries topped up without having to run the engine is a continuous challenge for cruising sailors, especially those…

I replaced our Bavaria’s standard 240Ah of domestic lead acid batteries with 800Ah of lithium batteries. The advantage of a lithium battery is its light weight. And, unlike a lead acid battery, it can be run down to a much lower charge. The downside is that lithium batteries have been known to explode.

To avoid this, they need to be paired with a battery management system, which is best left to a professional, who knows what they are doing, to install.

Oceanvolt lithium batteries aboard a Feeling 32

Charging sources

A standard ‘off the shelf’ mid-size production boat is likely to be fitted with a 60A battery charger which is used by the boat’s generator, if it has one, or when shore power is plugged in. The engine will also have an alternator which will typically produce between 35 and 60A of charge, depending on the size of the engine.

Assuming a 60A charge source, the batteries will receive 60A of charge in one hour. So, to put it very simplistically, if you have, as I do, 800Ah of lithium batteries and they are at 50 per cent, to charge them up to capacity would take 6.6 hours (400 amps divided by the charging source of 60 amps equals 6.6 hours).

Unfortunately, it’s not quite as simple as that. For example, there are various charging states – bulk, absorption and trickle (also known as maintenance or float) – and different types of batteries with different ratings, but I have kept it as simple as possible here for the purposes of explanation.

If you don’t have shore power (when at anchor, for instance), or don’t have a generator, the alternative is to run your engine for six hours under light load, which is not good for the engine and won’t win you many friends nearby who are trying to relax and enjoy a peaceful sundowner.

Mike’s customised electrical control panel

Battery charger

Increasing the size of your battery charger will speed up the process of charging from both a generator and shore power. I opted to fit a 120A charger and a 3kW inverter for my 240V appliances. There is always the option to beef up the engine alternator to feed a hungry family of batteries, but again, this means the boat engine needs to run for prolonged periods of time.

The 9kW Paguro 9000 generator I fitted produces a lot more power than we ever need. The generator powers both the 240V ‘ring main’ and the battery charger. However, the battery charging will be limited by the power rating of the charger, which in my case is 120A.

Four solar panels on Spirit’s stern arch produce a maximun 1,600W

Renewable energy

Renewable energy for boats is either wind, hydro or solar. I opted for solar on a custom-made stern arch. I fitted four 400W panels, which produce a theoretical maximum output of 1,600W at 12V or, in amp speak, 133A.

Like lithium batteries, the voltage and charge from solar panels needs to be managed, so each panel is equipped with an MPPT (maximum power point tracking) controller to ensure the batteries are getting the right amount of charge when the sun is shining. The next conundrum was to get all this in perfect balance based on the boat’s power consumption.

The stern arch was custom-built to support the solar panels

Background noise

I started by building a spreadsheet to calculate the various power ratings of my many onboard electrical appliances. However, this isn’t simple as you must calculate the power demand of each appliance, estimate how long you will run it for, and when you will run it.

You then need to map this over time to calculate a theoretical power demand and how much power you need to be generated. Estimating the power output from my solar panels alone became a headache: calculating the assumed number of ‘sunny’ daylight hours, the angle of the sun, solar panel efficiency, and when the next solar eclipse would be! So, like all people with limited brain capacity, I gave up.

I decided, instead, to take a more pragmatic approach. The first thing I did was to measure the ‘background noise’ of my boat; that is, the power being consumed whilst at anchor and not running any major appliances.

It turned out to be around 200A, which is very high; but then I do have three fridges, a deep freeze and more internal lighting than Blackpool Illuminations.

The time it takes to recharge my batteries once the sun has dragged itself up to the right angle differs dramatically based on which way the boat is lying. If my stern is exposed to the sunny side my batteries will fill to the brim in a few hours. However, if my bow is facing the sun, it takes a lot longer.

On an average day, we are at 100 per cent by midday or early afternoon, leaving a good four or five hours of surplus power generation for running more critical systems.

Air-con is a battery power ‘killer’

We have a lot of power consuming paraphernalia on board, for example the kettle, coffee maker, hair dryer, microwave oven, and so on, but I ignore these when it comes to power management as they are used randomly and are never on for long.

However, we do have several appliances that are critical to our power management, including a washing machine, water maker, ice maker and water heater. All of these have high demand and can run for long periods of time. I also have air-conditioning which can be run off the inverter, but I prefer to use fans and open hatches to keep the temperature tolerable when we are at anchor. Air-con is a battery power killer and is best left to when shore power is connected or the generator is running.

Our Bavaria came with a built-in utility room, so we decided to fit a full-sized washer-dryer, which has proven to be our favourite upgrade.

For this equipment I simply use a rota and allocate a specific day to run either water production, laundry, ice making or water heating. We do laundry once a week without using the drying function and relying instead on nature’s outside dryer, which does tend to lower the tone of an idyllic anchorage.

The water maker produces 60 litres an hour and I typically run it for around four hours, which will then keep us going for several days. I fit in ice-making and heating the water at other times.

Having guests on board who insist on having a shower every time they go for a dip off the swimming platform requires the water maker to be run most days. Inevitably under these circumstances I lose the battle of consumption versus generation and will need to resort to running the generator.

We chose a Schenker Smart 60-litre-per-hour, 12V water maker rated at 20A, which enables free freshwater production all day long thanks to Spirit’s cluster of four solar panels.

I always delay this until my battery charge is showing 30 per cent or less in the morning. At that point I will run the generator for three to four hours, which is enough to get my batteries back up to around 70-80 per cent, and then let the solar panels take over.

When I run the generator, I take advantage of the surplus power it produces by running as many devices as possible: I make water, run the air-con and heat water. Never waste any of those precious amps! I find that I run the generator, on average, every eight to 10 days when we’re on our own and every four to five days when we have guests.

Batteries can be easily distributed around a yacht

Before increasing the capacity of your service battery bank you need to calculate your total power requirement by multiplying the amperage of all the equipment by the period of time it will be run over a charge cycle (usually 24hrs).

Tally up the amp hours and then double the result (to allow for not going below 50 per cent of your charge capacity). Then add another 20 per cent to ensure you will always have enough to spare.

If you already have separate engine start and service batteries but want to add further service batteries, they should all be of the same age, type and capacity (Ah rating) to the first. It’s best to create your service bank from a number of smaller batteries and then link them together to achieve the total voltage and capacity you require.

If you’re planning to install a large bank (500Ah or more), it is often better to use 6V cells for this as these allow a large deep-cycling bank to be created, while still having the ability to move them around easily or distribute them evenly over a greater area.

Create an improved service bank by connecting a number of smaller batteries

Stay in charge

Once you’ve decided on the battery type, make sure you have enough charging power to fully charge them between cycles. As a rough guide you will need to be able to bulk-charge the bank at a minimum of 10 per cent of its rated capacity (ie. 20A for a 200Ah battery).

However, 20 per cent is a better figure to aim for if you’re looking to fully recharge over one night in a marina. Modern AGM (absorbent glass mat) style batteries can usually take a greater charge than wet lead-acid type, although gel cells require a more particular regime if they are not to be damaged.

Chargers (both mains and alternator regulators) should be of the multi-stage type, with bulk, absorb and float stages. This allows the batteries to be rapidly charged until they reach around 90 per cent charge, then the charge voltage drops to attain the final part of the charge more slowly, keeping temperature (and hence internal resistance) down, and eliminating gassing.

A smart battery monitor will allow you see your state of charge and remaining capacity

Temperature noticeably affects a battery’s ability to give out and absorb charge. The colder a battery gets, the greater the power required to charge it fully. For this reason, always fit a charger or regulator with a temperature sensor that will automatically compensate for these differences.

Most power devices produce a trickle charge, and are used to keep the engine battery topped up. However, if you’re planning to install a powerful (5A+) wind or water generator, or a large solar array, then you’ll need to install some sort of voltage regulator to prevent overcharging. This can vary, from a small solid-state switch for small solar panels, to a large dump resistor that dissipates excess charge from a wind generator through heating up a wire-wound resistor.

Monitoring your batteries

The easiest way to ensure your batteries are kept in tip-top condition is to observe their state of charge every day you’re on board, using a modern ‘smart’ battery monitor. This will give you a real-time display of the current going in and out, the state of charge (SOC), and the remaining capacity available. They also often have alarms to warn you when the voltage is dropping dangerously low, or if too high a charge is being applied.

A rough idea of the SOC can be attained using a voltmeter, but this is not particularly accurate and can indicate a false condition when recently charged or under a heavy load. It’s far better to install a monitor that has a shunt, which measures current flow over time and can calculate the available charge capacity remaining much more precisely.

Hydrogenerators, like this Remoran Wave 3, will quickly recharge a yacht’s batteries underway

Optimising solar power

The efficiency of solar panels can be compromised by saltwater and long-term exposure to UV and high temperatures. Good regular maintenance will improve a solar panel’s performance.

Clean your solar panels early in the morning, while they are at their coolest, as cleaning them when they are warm or exposed to direct sunlight can cause internal thermal stresses.

Use distilled or deionized water to avoid the formation of mineral stains or deposits on the surface of the panels, and avoid using harsh chemicals or abrasive solvents that could scratch the photovoltaic cells. Let the panels air-dry or use soft cloths, and make sure no water residue is left. Check regularly for cracks, breaks or loose connections.

Hydrogenerators

Hydrogeneration has become a great deal more efficient in recent years. It’s a very simple concept: the yacht’s motion through the water turns an alternator on the transom-mounted hydrogenerator which generates electricity to recharge the boat’s batteries. Achieving 300Ah each day is a realistic expectation when cruising at 7-8 knots.

Oceanvolt’s High Power ServoProp 25 electric saildrive

Main prop regeneration

You can also use your main propeller to ‘regenerate’ electricity whilst under sail by using a parallel hybrid propulsion system where an electric motor is installed alongside the engine. Lynch Motors in Devon has supplied its systems to Vendée Globe boats for years, purely as a re-generator, and now produces a Red Snapper electric motor for cruising yachts.

The only problem with a regeneration system is that the pitch required for the propeller to drive the boat efficiently through the water may not always be the same as the pitch for optimum regeneration. Manufacturers have tackled this in different ways.

Oceanvolt has developed its ServoProp for saildrives, which electronically adjusts its pitch depending on speed and function. The latest incarnation allows total 360° blade mobility and faces forwards, increasing efficiency: at six knots, it produces an eye-watering 1kW of power.

Bruntons has another solution with the cleverly engineered Autoprop, which automatically pitches up to match the boat speed. Its Ecostar version of the prop can generate 200W at five knots and up to 1kW at 10 knots when connected to an electric motor.

Enjoyed reading this?

A subscription to Yachting Monthly magazine costs around 40% less than the cover price, so you can save money compared to buying single issues .

Print and digital editions are available through Magazines Direct – where you can also find the latest deals .

YM is packed with information to help you get the most from your time on the water.

• Take your seamanship to the next level with tips, advice and skills from our experts
• Impartial in-depth reviews of the latest yachts and equipment
• Cruising guides to help you reach those dream destinations

Follow us on Facebook , Twitter and Instagram.

Berthon Winter Collection

Latest issue

August 2024

In the August 2024 issue of Yachting World magazine: News Few finish a tempestuous Round The Island Race European rules are eased for cruising to France and Greece Olympic sailing…

Yachting World

• Digital Edition

Best boat battery packs – 240V at sea

• Phil Sampson
• June 8, 2022

Phil Sampson checks out portable power stations that deliver 240V mains power in his guide to the best boat battery packs

When Joni Mitchell sang ‘You don’t know what you’ve got till it’s gone’ in her iconic song Big Yellow Taxi , she could have been singing about shore power. For as every yacht owner without an onboard generator discovers, the 240V AC mains supply we take for granted ashore becomes a distant dream whenever you leave the marina. Without mains power to recharge laptops and run kettles, microwaves and the like, life becomes more restricted.

While some might view 240V at sea as something of a luxury – after all, plenty of us have got by without it up until now – anyone who has spent an extended time on the water, especially at anchor without the engines running, will know that DC battery power is very much a finite resource. Cabin and cockpit lights, fridges and fans, or firing up the heater for a chilly night onboard, all take a battery-draining toll.

While a fully plumbed-in auxiliary generator provides the solution for larger yachts, the same does not hold true for smaller craft where engine room space and finances are often at a premium. Here, owners seeking mains power have traditionally either carried a portable genset – usually a low powered, noisy, smelly petrol-fuelled unit – or have simply gone without.

But now there’s another way: the portable electric power station. These rechargeable lithium-ion battery packs with built-in 240V inverters are small enough to tuck away under a seat or in a locker but many of them are also powerful enough to run energy intensive items like electric kettles. They are much less cumbersome than a traditional genny as well as being silent and emission free – ideal for occasional overnights at anchor or weekending aboard. In the same way that electric outboards are nibbling away at the market share of petrol-powered ones, portable electric power stations are now creeping quietly into the boating world.

The capabilities of these upstart interlopers vary widely but, as a general guide, the more you pay, the more portable power you get to take away.

Best boat battery packs

Jackery explorer 500 portable power station.

Jackery’s Explorer 500 Power Station is a 518Wh unit with three 12V DC outputs, three USB sockets and a UK three-pin 240V plug socket. The AC power output is 500W continuous and 1,000W peak. Jackery describes its Explorer 500 as a versatile green solar generator. That’s because when used in conjunction with the firm’s SolarSaga 100W solar panel, the unit’s lithium-ion battery pack can be fully recharged in around 9.5 hours. In 2016 Jackery won a prestigious Red Dot award for the design of its products. One notable feature on the Explorer 500 is the large LCD display showing the input/output power at any given time together with the battery charge status.

Buy it now at Amazon

Note: We may earn a commission when you buy through links on our site, at no extra cost to you. This doesn’t affect our editorial independence.

Poweroak portable power station 1500wh.

The 1,500Wh of power stored by the PowerOak PS8 EB150 means it is capable of running a 1kW travel kettle (or any other 1kW appliance) for 90 minutes non-stop – which of course nobody does. Estimating the time taken to boil a typical two-cup travel kettle as two minutes suggests this stylish power station would serve up to 90 brews on a single charge. The unit delivers its power via one of the two UK three-pin 240V AC sockets on the back of the box. In addition, the unit has five USB ports, including one USB-C outlet. An LCD display shows charging power, AC and DC output power, AC and DC on/off status, and a battery status indicator.

EcoFlow River PRO

While the EcoFlow River PRO is supplied as a 720Wh unit with a 600W output capability, it has a neat trick up its sleeve – a second battery can be added to double the energy storage capacity to 1,440Wh. And if you need more output power, that’s not a problem either as the unit features what EcoFlow calls its X-boost mode.

This allows the River PRO to power devices up to 1,800W, which covers around 80% of kitchen appliances and DIY tools. Solar panel recharging times of as little as four hours are possible by using two EF 11W solar panels (sold separately), while the unit can be recharged from the mains from zero to 80% in just one hour, with a full charge achieved in 1.6 hours.

EcoFlow Delta

Packing a 1,260Wh punch, the EcoFlow Delta is a fully-featured portable power station with four three-pin 240V AC 1,800W (3,300W surge) sockets, six USB outlets (two USB-A, two fast charge and two USB-C) and a 13.6V car cigarette lighter-style socket. That means it is theoretically possible to run up to 11 appliances at once, although the power would quickly drain at that rate. The EcoFlow Delta can run a mains appliance such as a microwave for 1 to 1.8 hours or a TV for up to 16 hours. It will also power a coffee machine long enough to deliver between 50 and 60 cups. An additional bonus offered by the EcoFlow Delta is its solar panel/car cigarette lighter input which allows the unit to be recharged either by solar or car battery power.

Poweroak Portable Power Station 500Wh

This compact 500Wh Bluetti PS6S portable power station features two 240V outlets providing up to 300W of AC power, which makes it capable of running products such as a mini-fridge. There are five USB points, including a USB-C socket, two 12V 3A sockets and a 12V 9A cigarette lighter outlet. Poweroak says the onboard lithium-ion battery cell is good for more than 1,000 cycles, and an in-built multi-protection system guards against over-voltage, over-current, over-temperature and short circuit. Recharging takes 6 to 6.5 hours using the included AC adaptor/generator, or 6 to 7 hours using Poweroak’s SP120 120W solar panel (sold separately). Includes a 24-month warranty.

Festool SYS-PST 1500

The big daddy of our pick of portable power stations, the Festool SYS-PST 1500 delivers a mighty 2,990W of permanent power and up to 11,000W in a short-term burst. Despite this hefty performance the unit is not too heavy or large; it weighs 16.5kg and measures 396 x 296 x 187mm. A full recharge takes three hours, with a built-in smart charging system protecting the battery cells while charging is under way. In addition to a single 240V UK three-pin outlet, the unit also provides 5-20V via a USB-C connection. Designed primarily for the construction industry, the SYS-PST 1500’s lithium-ion battery stores 1,500Wh of energy. This, Festool claims, is sufficient to run all the tools a builder typically uses for an entire working day – and as the average skipper is likely to demand much less power than a tradesman, it should run for considerably longer on a boat.

Buy it now at Festool

If you enjoyed this….

Yachting World is the world’s leading magazine for bluewater cruisers and offshore sailors. Every month we have inspirational adventures and practical features to help you realise your sailing dreams. Build your knowledge with a subscription delivered to your door. See our latest offers and save at least 30% off the cover price.

• Marine Supplies
• Maintenance & Boating Guides

Accessories

The 6 Best Marine Batteries in 2022

By: Kye Cardinalis Editor

If you are looking for a starting battery or deep cycle battery for your boat, you must choose a battery that can provide you with the power and performance you need for your engine or appliances.

At the same time, you will also need to consider additional features such as the battery management system, leak and vibration resistance, battery cycle life, and more. In this post, we will share our recommendations with you for the best marine batteries for trolling, cold climates, portability, and other categories.

To learn more about important considerations when choosing a marine battery, scroll down past the product overviews for the buying guide.

Best Deep Cycle Marine Battery

1. LOSSIGY Lithium Battery 12V 100Ah Lifepo4 Deep Cycle Battery

What we like

• Grade A cells.
• Light and portable.
• Built-in BMS.
• Nice customer service.

What we don’t like

• Rarely, a short-life battery may appear.

Our top recommendation for a house battery is the LOSSIGY Lithium Battery 12V 100Ah Lifepo4 Deep Cycle Battery. This also is our top pick for a lithium battery, offering high discharge efficiency compared to a traditional lead-acid battery. We could also list it as our top pick overall, as we are impressed with its waterproof construction, built-in BMS, and extremely long potential lifespan.

Key Specifications

• Available in 12.8V or 25.6 volts
• Available in 8-400 Ah
• Built-in BMS
• 4000-7000 cycles
• IP 68 waterproofing

What We Like

• This battery provides the reliable power you need to keep your boat appliances powered at sea. You’ll be impressed with the high energy density of the Grade A cells.
• This battery is fairly lightweight and features a convenient carrying handle, making it more portable than some competing batteries.
• BMS is built right into the battery, so it is safe from overcharging, short-circuiting and overheating.
• If you take good care of this lithium battery, you can get up to a decade of life out of it. You can receive free service for 5 years after you purchase it.
• You probably will not need to avail yourself of customer service, but if you do, you will be pleasantly surprised by how responsive, friendly and helpful the team is.

What We Don’t Like

• Occasionally this product seems to quit after around six months. Most users do not report this, so it could be either a rare quality control issue or the result of user error.

Best Marine Starting Battery

2. Optima Batteries 8006-006 34M BlueTop Marine Starting Battery

• Vibration-resistant design.
• Versatile mounting options.
• Practically requires no maintenance.
• Sometimes, for some reason, Optima appears to send out outdated batteries.

The Optima Batteries 8006-006 34M BlueTop Marine Starting Battery provides the cranking power you need to start your boat engine. What we really like about this battery is how good a job it does holding a charge between uses (especially if you remember to disconnect it). They are a great choice for a starting battery all around, but those who only take their boats out occasionally will really appreciate the excellent charge holding.

• 800 cold-cranking amps
• 10″ x 6 7/8″ x 7 13/16″
• 38.4 pounds
• 100-minute reserve capacity
• This starting battery is very robust thanks to its vibration-resistant design. It is also spill-proof.
• The versatile mounting options should be a fit for just about any situation.
• The spiral-wound continuous lead plates make for excellent precision in the manufacturing of the battery.
• If you use the battery properly, it should require no maintenance.
• Occasionally for some reason, Optima seems to ship out old batteries when you order these. It is worth checking the date on your starting battery before you install it.

Best Dual-Purpose Battery

3. Optima OPT8016-103 Batteries D34M BlueTop

• Vibration resistance and a spill-proof design.
• Zero-maintenance design.
• Multifunctional.
• Some short-life battery may appear.

The Optima OPT8016-103 Batteries D34M BlueTop is similar to the Optima Batteries 8006-006 34M BlueTop Marine Starting Battery, with many of the same basic features. But unlike that battery, this one can be used as a starting and house battery.

• 750 cold-cranking amps
• 10 inches x 6 7/8 inches x 7 13/16 inches
• 43.5 pounds
• 120-minute reserve capacity
• As with the other Optima battery we featured, this one offers superior vibration resistance and a spill-proof design.
• The zero-maintenance design lets you focus on boating and not on battery upkeep.
• The reserve this battery can hold is impressive given its lightweight design.
• While a lot of dual-purpose batteries are not as good for either application as sole-purpose starting or house batteries, this one admirably pulls its weight in both departments.
• Now and again, one of these batteries will die around the 1-year mark. Thankfully, this is not common.

Best Trolling Motor Marine Battery

4. Odyssey 34M-PC1500ST TROLLING Thunder Marine Dual-Purpose Battery

• Long-lasting.
• Vibration-resistant build.
• Extreme temperatures resistant.
• Requires zero maintenance.
• Rarely malfunctioned batteries may ship.

Looking for a battery for a trolling boat? The Odyssey 34M-PC1500ST TROLLING Thunder is designed expressly for that purpose. With its high cranking power and reserve capacity and its impressive dual-purpose design, it can get your motor running and power your appliances for longer than many competing products.

• 880 cold crank amps
• 13.25 x 11 x 9.5 inches
• 49.5 pounds
• This battery can last for up to a decade. It also can go 2 years without recharging in storage.
• The manufacturer states that this product features the “ highest recharge efficiency of any sealed lead battery on the market.”
• The vibration-resistant build offers excellent durability. It has a US Department of Transportation classification as being spill-proof as well.
• You can use the battery in temperatures as low as -40 degrees Fahrenheit or as high as 176 degrees Fahrenheit, making it suitable for all climates.
• You never have to worry about putting water in this battery; it requires zero maintenance.
• As seems typical with marine batteries, there is sometimes a dud that will not hold its charge after some months go by. But most of these Odyssey batteries will stand the test of time.

Best Portable Marine Battery

5. ECO-WORTHY Portable 12V Lithium Battery

• Lightweight.
• Fast charging.
• 3-year warranty.
• Can be lacking the documentation to register the warranty.

If you are looking for a marine battery that is compact and easy to carry, the ECO-WORTHY Portable 12V Lithium Battery may fit the bill. At under 5 pounds, it is astonishingly lightweight and portable. Consider pairing it with one of the 60W or 100W solar panels the manufacturer makes.

• 7.8 x 4.1 x 4.3 inches
• More than 4,000 cycles
• This battery is ridiculously lightweight. If you are carrying it in a backpack, you could easily forget it is even in there. Nonetheless, it can replace some heavier batteries on the market and offer just as much power.
• Rapid charging means this battery is ready to use when you need it.
• The clever design has holes built into it that allow heat to escape, preventing the battery from overheating during use. BMS is also built-in for added protection.
• The product is backed by a 3-year warranty.
• When you receive this battery, it can be lacking the documentation you need to register for the warranty or get up and running with comprehensive instructions.

Best Marine Battery for Cold Climates

6. JITA Low Temperature Charging (-31°F) LifePO4 Lithium Battery

• Smart heating function.
• You can connect these batteries in parallel.
• IP65 waterproofing.
• Up to 10 years of life and 5-year warranty.
• Occasionally, a dud ships out.

If you need a battery you can charge in cold conditions, you can consider the JITA Low-Temperature Charging (-31°F) LifePO4 Lithium Battery. This product contains a heating film. When temperatures are below freezing, the BMS directs power to a heating film. It then switches the heat function off at 50 degrees Fahrenheit. This is an excellent premium feature that you will not find in just any marine battery.

• Available in 12, 12.8, or 24 volts
• Available in 18 to 300 Ah
• Up to 5,000 cycles
• Thanks to the smart heating function, you can count on this marine battery even on the coldest days.
• The exact weight of the battery depends on the size you get, but in general, these are quite lightweight.
• You can connect these batteries in parallel if you require more voltage.
• The ABS hard case and IP65 waterproofing make for a rugged battery that can withstand rough seas.
• You can get up to 10 years of life out of this marine battery, which is backed by a 5-year warranty.
• Occasionally, a dud ships out. The good news is that customer support is awesome about arranging swift exchanges if necessary. So, be sure to test your batteries when they arrive.

What to Look for in a Marine Battery

You have now had a chance to check out some of the most durable, powerful, versatile marine batteries on the market.

But if this is your first time shopping for a marine battery, you might not be sure which of the options we recommended you need. Below are some key considerations that can help you narrow down your choice.

– Marine battery purpose: The two main types of marine batteries are starting batteries and deep-cycle batteries ( 2 ). As you would guess, a marine starting battery is what you use to start the engine of the vessel. A marine deep cycle battery, on the other hand, is also called a “house battery.” Use it to power onboard appliances. Don’t have room for two batteries? Consider a dual-purpose battery that merges both functions.

– Battery type: You can choose between lithium, lead-acid wet-cell batteries, and absorbed glass mat (AGM) batteries for your boat. You can go with lead-acid wet-cell batteries if you are on a budget, but AGM batteries are zero maintenance and last longer. Lithium batteries last the longest and are lightweight and powerful.

– Weight and Size: Make sure the marine battery you are thinking of buying will be the right size to fit in your vessel. Also, consider the weight; it is not uncommon for a marine battery to weigh in excess of 50 pounds. But some models weigh under 30 pounds or even less. A compact, lightweight design may also be important if you plan to move the battery around a lot (i.e. to use it for different applications such as your boat and your RV).

– Power: Choose a marine starting battery that has enough cranking power to get your engine running, even if it is cold. If you are shopping for a deep-cycle battery, pick one that will be sufficient to power your appliances. You will need to check your individual power needs to know how much power you require in a battery.

– Mounting requirements: Depending on the product you buy, there may be different mounting options available. Choose a product that is compatible with your needs.

– Vibration resistance: The more vibration a battery can withstand on a boat, the more durable its construction will be.

– Leak resistance: Get a battery that has a leak-resistant design so toxic chemicals will not escape the casing.

– Battery management system (BMS): Some batteries include a built-in system for battery management that helps to prevent overheating, short-circuiting, and other potential issues that could fry your battery. A BMS can protect the life of your battery and increase the safety of its use.

– Operating temperatures: If you live in a climate that regularly gets to be very hot or cold, it is important to know not all batteries will necessarily operate in your climate conditions. Be sure to check the full range of operating temperatures so you can get a marine battery suited to your region.

– Cycle life: The number of cycles tells you how many times you can charge and discharge the battery before its performance declines. The more cycles, the longer the lifespan of the product.

– Warranty: As batteries can sometimes quit a year or two in, the warranty is particularly important. If it is several years or longer, you can use your marine battery with greater peace of mind.

– Marine battery prices: Most marine batteries sell in the range of $100-$400, though some are more or less expensive. There are some surprisingly good budget options out there, but the best marine battery for the money often will fall into the mid-price range. You may need to purchase a premium battery for high Ah.

You might also be interested in:

• The 5 Best Solar Battery Chargers for Boats in 2022
• The 5 Best Electric Anchor Winches

Frequently Asked Questions About Marine Batteries

Anywhere from 2-5 years is a typical lifespan for a marine battery. If you want your batteries to last as long as possible, you must take care to set them up and maintain them properly. Oftentimes, it is the mistakes of boat owners rather than manufacturers that cause marine batteries to fail early (2).

That depends on the type of marine battery you have. For a deep cycle battery, you will need a deep cycle charger. For a lithium battery, you need a lithium battery charger, etc. Once you have the appropriate charger, clean the battery terminals, hook up the cables, plug in the charger, and turn it on. Once charging is complete, disconnect the charger from the battery.

Consider choosing a reputable brand like Odyssey, Optima, or another from this list.

The best marine battery from a longevity standpoint is a lithium battery. These may last up to 10 years, depending on use.

That depends on your engine and how much power it requires for you to start it. This varies from one engine to another, so you will need to check your engine specs before you choose a marine starting battery.

MCA stands for “marine cranking amps.” It tells you how many amps your engine will receive at 32 degrees Fahrenheit. A related rating is CCA, which stands for “cold cranking amps.” This rating tells you how many amps your engine will receive at 0 degrees Fahrenheit. Which rating you should pay attention to depends on the conditions in which you expect to need to start your engine. What is most important is simply not to mix up the two ratings.

Troubleshooting Pontoon Boat Battery

Pontoon boats are a great way to enjoy the water and spend quality time with family and friends. But just like any other boat, they rely on a battery to power various systems, including navigation lights, trolling motors, and other…

Boat Accessories

Best Ice Fishing Fish Finders in 2023

In search of the best ice fishing fish finders in 2023? Not all fish finders are created equal, particularly when it comes to ice fishing. Specialized features are crucial to ensure successful outings in harsh winter conditions. You require a…

Best Side Imaging Fish Finders in 2023

Navigating the world of angling equipment can be challenging. That's especially true when it comes to side imaging fish finders, given the extensive range of options available in 2023. This post makes it easy for you to narrow down your…

How to Choose a Fishfinder for Your Boat: A Comprehensive Guide

Today, we embark on a journey to unravel the secrets of choosing the perfect fish finder for your boat. As we navigate through an ocean of options, we'll explore different types of fish finders, delve into their key features, and…

5 Best Portable Fish Finder in 2023

Looking for a portable fish finder for kayaking, ice fishing, or other activities? The good news is that there are a lot of solid products out there. The year 2023 has ushered in an array of advanced models, each brimming…

Charging Your Trolling Motor Battery with a Solar Panel

Charging your trolling motor battery with a solar panel is not just the right thing to do for the environment, it is extremely convenient. When you’re out on the boat, with any luck, you’ll have access to a good amount…

Don't miss out

• Portable Refrigerators
• Power Inverters
• Marine Batteries
• Best Marine Boat Batteries – A Complete Guide

Best Marine Boat Batteries – A Complete Guide

Best marine boat batteries.

Below is our selection for the best marine batteries. While these are our top picks, be sure to read the remainder of the article to ensure you are purchasing the right battery for your needs. Links will open in a new tab.

Best Cranking / Starting Marine Battery

Optima bluetop starting battery.

For a starting battery, you need one that’s going to be reliable, durable, and able to perform when you need it to. That’s why the Optima BlueTop Starting battery is our top pick for a cranking/starting battery. Optima is a well-known brand and uses spiralcell technology to build their batteries which offers a more energy-dense cell.

>> Check the Price on Amazon

Best Deep-Cycle Marine Battery

Renogy 100ah deep cycle pure gel battery.

Renogy is better known for their solar power charging kits, which you should check out if you’re in the market for one. However, they make a pretty damn good battery too. With or without a solar kit, this battery simply performs. Utilizing high purity lead and a patented gel electrolyte, this battery is the best deep-cycle option available. A perfect option for building a battery bank.

Best Trolling Motor Battery

Greenlife gl lithium-ion series or universal deep cycle agm.

For small watercraft weight tends to play a factor in the battery you purchase. If you have the funds, purchasing a lithium-ion battery is ideal. Lithium ion batteries are incredibly lightweight, and are very compact compared to other types. Depending on your power needs, a 50Ah or 100Ah is the way to go.

For 50Ah (pictured), try the GreenLife GL50 50Ah Lithium-Ion Battery . For 100Ah, try the GreenLife GL100 100Ah Lithium-Ion Battery .

Best Lithium-Ion Battery

Renogy lithium-iron phosphate 100ah battery.

Renogy takes another spot! Offered both in 100Ah, and 170Ah options, their lithium-iron (yup, you read that right, lithium -iron ) phosphate batteries are a fantastic option for storing energy for multi-day use. If you plan on building a battery bank and have a larger budget, this is the way to go. The 100Ah model weighs under 30lbs, and the 170Ah model weighs less than 50lbs.

Best Boat Battery Value

Universal 100ah deep cycle agm battery.

Nothing fancy about these batteries, but they’re tough and they’ll do their job. This is the economic option for a deep cycle AGM style battery. Each puts out 100Ah and if you’re working on a budget battery bank or need to replace another deep cycle battery and keep it cheap, here’s your best option.

Best Battery for Boat Lift Motor

Expertpower 33ah deep cycle battery.

You’ll want to consult the owner’s manual for your boat lift, but you generally won’t need a battery with a lot of power. ExpertPower’s battery is an AGM 33Ah deep-cycle battery. Hook this up to a drip feed solar charger and you’ll have all the power you need to operate your lift whenever you need it.

Best Dual-Purpose Marine / RV Battery

Odyssey thunder marine dual-purpose battery.

Don’t have the space for a cranking battery and deep-cycle? Here’s your next best option. Odyssey batteries are built to last. They’re strong, reliable, and have a strong warranty behind them. This model in particular provides 880 CCA and a RC of 135 minutes. Perfect for a boat or RV.

Types of Marine Batteries

Buying a battery for a marine vessel is a little bit different than buying one for your car or truck. There’s different types of batteries and different needs that need to be taken into account throughout the purchase process. By the end of this guide, you’ll have answers some of the most common questions like:

Cranking (aka starting) vs. Deep-Cycle Boat Batteries

What is a cranking  or starting boat battery.

Whenever starting any sort of large engine, whether a boat or a car, there’s a large amount of energy needed in a short amount of time. In order to provide this burst of energy, cranking, or starting, batteries are designed with this intent in mind. No need to get into what these batteries look like on the inside just yet, we’ll cover that shortly.

What to look for

Most likely you’re boat came with a battery, which should be a good indicator for the kind of Marine Cranking Amps, or MCA, you’ll need for you new battery. Regardless, it’s recommended to check the owner’s manual to be sure the battery in previously was providing enough power. The MCA rating on the new battery needs to meet or exceed the recommended rating.

If your boat is recommended to have a 700 MCA battery, you’ll need a 700 MCA or 700+ MCA rated battery. A 800 or even 900 MCA battery will work just fine. Just be sure to take measurements of the old battery, or better yet, take it with you. The new battery will have to fit in the limited space the old battery was living in.

What is a Deep-Cycle Boat Battery?

If you have a trolling motor on your boat or plan on constructing a battery bank, a deep-cycle battery is the way to go. A deep-cycle battery is different from a starting battery in it’s meant for a longer, slower pull of power. Instead of a quick burst in a second or two, these batteries are built for hours of gradual pull.

If all you’re powering is a trolling motor and a few small accessories, you’ll be able to add up the power usage from those, the estimated time you’ll be using them and make some calculations. There are other factors you will need to account for such as depth of discharge. DoD is basically how much of your battery use before recharge. Since it’s not good to run batteries all the way to 0%, most manufacturers recommend not going anywhere below 20%-25% of power. Doing so significantly reduces the battery’s lifespan.

The exception to this rule is lithium-ion batteries. A lithium-ion battery can run 100% DoD, without harm to the battery. However, with all batteries, the shallower the discharge, the more cycles you’re able to get out of the battery. For example, if you get get 1000 cycles out of a battery at a 50% DoD, then you may be able to get 1200 cycles at a 70% DoD, ignoring other factors.

For even smaller batteries, some manufacturers do not recommend going below the 50% threshold. Your functional power is essentially cut in half.

If you have a lot of gadgets to power, BatteryStuff.com has a simple calculator . (Opens in a new tab)

A Realistic Example

Let’s say you have a single trolling motor that provides around 40lbs of thrust. This is roughly 2/3 of a HP, 500 watts, or 40 amps at 12.6 VDC. Here, were rare assuming 746 watts equals a single horsepower and 58lbs of thrust equals a single horsepower.

You decide to purchase a deep cycle wet cell battery which has a 100Ah (Amp hour) rating at 20 hour rate, meaning it functions at a draw of 5 amps per hour. Since this is a smaller battery, you won’t want to discharge this past the 50% point, leaving you with about 50Ah of functional power.

If you use the battery for 30 minutes every time you’re out fishing, the result is 20Ah of use (.5 x 40 amps). With 50Ah of functional power, you could take 2, 30-minute trips before needing to recharge the battery. However, these calculations don’t take into account other factors, like battery age, temperature, etc.

In a perfect world, you could get 2, 30-minute trips. However, in reality you’re safe getting in that single trip with some extra time to spare if you want to take the long way home. Rate of discharge and other accessories will draw power from the battery and simply said, you’ll want to charge the battery after every trip.

A Word of Caution

Do not switch out one battery type for the other. These batteries will be clearly labeled and if for some reason the label has become unreadable, don’t risk it. Using a cranking battery in a deep-cycle application will cause it to overheat, fail, and / or possible start a fire. A deep cycle battery in a cranking application typically won’t work. In the event it does, it’s likely to not start up the second time since deep cycle batteries take a significantly longer amount of time to charge. Better to be stranded ashore, then on the water.

Other Factors

Temperature.

Batteries don’t like the cold! In colder climates, and generally any temperature below 70 to 80 degrees Fahrenheit, you’ll likely see a drop in performance. In sub-freezing temperatures, wet-cell batteries can even freeze and become useless. There isn’t a hard-and-fast rule for battery usage in colder climates, but just know you’ll likely need a stronger battery if the weather around you isn’t 70+.

Additionally, wet-cell batteries self-discharge during warmer temperatures at around 1% every 24 hours. In a few weeks’ time, it’s not unlikely the battery could have lost 20Ah of power. It’s recommended to purchase a solar panel charger in order to prevent this. More on solar chargers here.

The rate at which power is drawn from the battery also has an effect on the battery’s lifespan and use. This pertains more so to deep-cycle batteries. When a lot of power is drawn in a short amount of time, this not only shortens the lifespan, but also lessens the total functional power you can utilize. A significant portion of that energy is lost as heat.

Dual-Purpose Batteries

If you’re town between a cranking battery and a deep-cycle battery, there is a middle ground! Dual-purpose batteries give the best of both worlds without having to worry about frying a battery in the process. If possible, it’s best to have a separate starting battery and a separate deep-cycle if you have the need for both types. However, there scenarios where that isn’t possible, like if you’re limited on space.

For a dual-purpose battery, you’re looking for the same factors and specs you would on a cranking or deep cycle battery. You need to make sure your CCAs meet or exceed the requirements of your motor, and make sure the reserve capacity will suffice for your intended usage.

Four Types of Batteries: Wet-Cell (aka Flooded, Flooded Cell, Lead Acid), Gel, AGM (Absorbed Glass Mat), and Lithium-Ion

Wet-cell batteries.

Wet-cell, or flooded-cell batteries are your most basic batteries in boats, cars, SUVs, trucks and pretty much anywhere you need to draw a large amount of power in a short amount of time. They’re the most affordable option available, but also tend to require the most maintenance.

These batteries contain many lead plates that live in a mixture of distilled water and sulfuric acid. While we won’t get into how they work (that was for high school physics), the important thing you need to know is they’re capable of up to 1000 discharge/recharge cycles. This means they can last for years if well taken care of, at a low cost.

These batteries are less likely to be damaged by overcharging and for weight to energy output, they tend to weight the least. The problem with these batteries is you need to be checking the water levels to ensure they’re full. The additional problem with having to check these levels is insides of the battery are accessible which means they could potentially spill or leak battery acid in applications where there’s lots of movement – like a boat. When opened these batteries release hydrogen gas, which is flammable, so maintenance needs to be done in a well-ventilated area.

Lastly, these batteries do self-discharge. So when left off of a charger and not being used they typically discharge somewhere between 1% a day to 7%-8% per month, depending on factors like age and temperature.

Gel Batteries

Gel batteries solve many of the problems wet-cell batteries have, but at a cost. These batteries are sealed at the time of production, so these batteries are maintenance free. Instead of lead plates living in an acidic solution, these batteries are filled with a liquid electrolyte that is gelled with silicates.

As mentioned earlier, these batteries are meant to be used (or discharged) at lower rates over longer periods of time. Because of these, they can be stored for extended periods of time without worrying about losing power. Compared to a wet-cell’s of up to 1% per day, these batteries lose less than 1% of power per month.

Downside to these batteries is they’re typically more expensive and a special charger, or at least one with a gel-setting needs to be used. These are recommended to be charged to 13-14 volts.

AGM Batteries

AGM stands for Absorbent Glass Matting, meaning these batteries are composed of a dense filling of glass threads that are woven together to form a literal mat. These designed to wick the battery electrolytes between the lead plates.

Similar to gel batteries, these are sealed at production, meaning essentially no maintenance is required but some external cleaning. The downside to these batteries is they are sensitive to overcharging (rendering them virtually dead if overcharged), and are more expensive than their wet-cell cousins.

Lithium-Ion Batteries

Whether or not you know it, you use lithium-ion batteries on a daily basis. They’re in our cars, phones, power tools, and other electronics. The largest benefit with lithium-ion batteries is their lifespan and the energy density. Compared to other battery types they can hold more energy in a smaller amount of space and for a longer period time. When it comes to weight, these batteries win again. A 100Ah battery will usually weigh around 30lbs or so, compared to a AGM that will weigh 70lbs+. Lastly, there isn’t any reason to worry about depth of discharge. Lithium-ion batteries can be fully discharged without damage – this makes them great for building a battery bank.

The downside is, these batteries are far from cheap, however, they will typically last up to 7-10 times longer than some of the batteries already mentioned.

Other Specifications

Cca vs. mca vs. hca.

Marine Cranking Amps and Cold Cranking Amps are essentially the same thing, just with a 32 degree Fahrenheit difference. You may see that your car battery has a CCA rating. What the CCA rating means is it tells how many amps the battery can send for 30 seconds at a 0 degrees Fahrenheit before the voltage drops to 1.2V per cell or 7.2V for a 12V battery.

Thus a 12V battery rated at 800 CCA, will provide 800 amps for 30 seconds at 0 degrees Fahrenheit before the voltage drops to 7.2V.

MCA on the other hand, is same measure, but at 32 degrees Fahrenheit. Sometimes ‘MCA’ is simply referred to as ‘CA’, or ‘Cranking Amps’. So, a battery rated at 1000 MCA (or CA), will provide 1000 amps for 30 seconds at 32 degrees Fahrenheit before the voltage drops to 7.2V.

HCA is less common, but sometimes you’ll see this rating too. HCA stands for Hot Cranking Amps and refers to the same measurement, but at 80 degrees Fahrenheit.

Reserve Minutes

Earlier we went through the calculations for a battery powering a trolling motor. There is another measure you can use for either building a battery bank or powering a trolling motor and that’s the reserve minutes, or also called the ‘reserve capacity’. This measure is expressed in minutes and tells how long a fully charged battery can provide a constant load (typically 25 amps), before it’s fully discharged.

For a 12V battery, it is fully discharged, once it has fallen to 10.5 volts.

The group size is a categorization given by Battery Council International , or simply BCI. These sizes are apply to all battery types, including automotive, utility, and commercial applications. There’s a lot of different sizes and if you really want to dive through all of them, a chart is on this site here .  Group size isn’t super important, just make sure you take your old battery with your to compare sizes and purchase a battery with the same or higher CCAs.

Tips for Optimal Battery Performance

General maintenance.

This is specific for wet-cell batteries but cleaning any sort of corrosion that builds up around the terminals is a must. Too much corrosion can lead to a bad connection. Use a disposable shop towel to wipe away corrosion and other debris into a trashcan – don’t sweep this into the water.

If the corrosion is really bad, you’ll want to remove the connections and take a wire brush to terminals and wires. Once the metal has been cleaned, using a battery corrosion preventative such as NCP2, is highly recommended.

Lastly, doing some basic visual checks can go a long way. Make sure the case isn’t bulging or cracked. This could indicate overcharging and you will want to check your charger and alternator as well.

Winter Storage

If you’re winterizing your boat, you will want to full charge your battery and then disconnect them from the terminals. If you have a flooded cell battery, be sure it has enough water before charging. Depending on how long the battery is in storage, you’ll want to check it periodically and ensure it’s fully charged. If you don’t have the ability to check/charge the battery on a least a monthly basis, it’s highly recommended to purchase a trickle charger or a solar trickle charger if left out in the sun.

Consider a Battery Box

A battery box is exactly what it sounds like – it’s a protective housing for your battery. A battery box is excellent protection against the elements while still allowing the cables to be ran inside of the box. Boxes are typically vented to allow any gasses that might need to ventilate. These boxes will collect any battery acid that may leak and they make it incredibly easy to tie down and secure the battery.

Charging and Discharging

As was mentioned earlier, batteries should not be pushed past their depth of discharge as specified by the manufacturer. For deep cycle batteries, they should not go below a 20% capacity, with starter batteries, they generally shouldn’t go below 70% of their charge.

Always charge your batteries after use and do not mix different types of batteries together. Whenever replacing a battery, be sure all the batteries in your system are replaced at the same time. Older batteries tend to decrease the lifespan of new batteries. Never leave batteries deeply discharged for any significant period of time.

What to do with old batteries?

Whenever you purchase a new battery, automotive, marine, or whatever, there will be a core charge added to the cost. This will depend on the size of the battery, but it’s typically around $10-$20 in the US. This core charge is refunded when an old battery is returned to be recycled.

Most of the time, if you have multiple batteries, retailers will be happy to take those batteries off your hands for recycling. Home Depot, Lowe’s, AutoZone, and Rural King are a couple just to name a few. Be sure to call ahead to check. Otherwise, check with your city’s recycling program. EarthCity911.com and  Call2Recycle.Org are also 2 additional resources that can point you in the right direction.

Boat Battery FAQ

Can a boat battery get wet.

A marine grade battery can get wet, but only to an extent. Don’t forget, we’re dealing with electricity here. Electricity and water don’t mix, so avoid contact as much as possible. No battery should ever be sitting in any pool or puddle of water. However, most batteries will be fine if they get a little bit of rain on them. It’s highly recommended to store your battery in a battery box to protect it from the elements.

Can a boat battery be used in a car?

It depends on the application. If you plan on using it to start the car, then you need to use a cranking battery that meets the CCA required by your vehicle’s 12V electrical system. In general, if you’re using a cranking battery and the boat battery meets or exceeds the vehicle’s requirement for CCA, then yes you can.

Can you overcharge a boat battery?

Yes you can. While certain batteries are more sensitive to overcharging, like the AGMs mentioned in this article, all batteries can be overcharged. Once overcharged, they can be dangerous to handle and rendered almost useless in certain situations.

What boat battery do I need?

The type of battery you will need depends heavily on the use and requirements of your boat. Generally speaking, if this battery is only used to start up the motor, then a cranking battery is needed. If you are using a trolling motor or looking to power electronics on board, you’ll need a deep-cycle battery.

How long will a boat battery last?

The lifespan of a boat battery will vary greatly based on age, climate, use, and other factors. As each year passes, the total lifespan of the battery loses its ability to hold a charge. For example, a battery that could provide 100% of power at the start of its life, will likely only be able to provide 75% of its total power in 3 years. This number begins to increase significantly has time goes on.

How do I test a boat battery?

To check the voltage of any battery, you’ll need a multimeter. These can purchased fairly inexpensively from Amazon or your local hardware store. To test the battery you’ll want to disconnect the battery from the boat, set the multimeter to DC (or direct current), and connect the alligator clips to the correct terminals.

A fully charged battery will be around 12V or higher. If the reading comes less than 10.7V to 11V, it may be time to replace the battery. You may opt to purchase a multimeter than can perform a load test. A load test is simply a measure of how the battery performs under simulated use. While under a load test, the reading should be somewhere around 9.5V to 10.5V for 30 seconds total.

How do I charge a boat battery while out on the water?

To charge a boat battery while on the water you must have a charger or alternator built into your engine or some other means of replenishing power such as through a solar charger.

Do outboard motors recharge the battery?

Yes, most modern outboard motors have an alternator built-in to recharge the battery.

Take me back to the top to browse batteries!

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Other Posts You Might Like...

You may also like, best marine battery chargers and reviews, how to wire 12v & 24v battery bank in series or parallel, best deep cycle batteries – an informative guide, best trolling motor propellers, 3 reasons to buy a trolling motor foot pedal tray for your boat, 4 steps to charge a deep cycle battery properly, how to winterize your boat, best power inverters – the complete guide, best portable refrigerators – the complete guide.

• Spirit 1.0 Plus
• Spirit 1.0 Evo
• Pod Drive Evo
• E-Series Battery
• G102-100 Battery
• Find a Dealer
• Have a Dealer Contact Me
• Product Registration

• Support Center: FAQ & Guide
• Video Tutorial
• Download Center
• Performance Bulletins

Outboard Motor Battery: What Size Do I Need & What’s Best for My Boat?

New to boating and trying to figure out what outboard motor battery you need?

However, you might get overwhelmed by the vast choice of outboard motor batteries in the market.

To name just a few: marine batteries, lithium batteries, lead-acid batteries, AGM batteries, deep cycle batteries, starting or cranking batteries…

And all outboard motor batteries are available in various volts, sizes, brands, etc.

The more you search online, the more confused you might be.

You are not alone! Here we will explain all your confusion in a simple guide.

If you are one of those who are trying to figure out the battery needs for your boat (types, sizes, etc), read this post to find quick answers.

Besides that, you will also learn about outboard motor battery wiring and charging in minutes.

Table of contents:

Outboard Motor Battery Types

Electric boat motor battery sizes, best outboard motor battery, outboard battery wiring, outboard motor battery charging.

• FAQs About Outboard Batteries

What kind of battery do I need for an outboard motor?

You might have seen outboard motor batteries with confusing labels. In fact, they are categorized according to their purposes and chemistry.

2 Types Based on Purposes

Basically, all outboard motor marine batteries serve two purposes: starting the engine or running the electrical load onboard. This divides outboard motor batteries into two types.

• Starting Batteries

As the name implies, a starting battery (or cranking battery) is ultimately designed to start the engine. This kind of outboard motor battery comes with high CCA values, providing high current surges and cranking amps to start your engine.

If using the wrong battery that’s not designed for a starting (or high-power) application, you will have a high chance of starting a fire in the voltage regulator and killing the battery.

• Deep Cycle Batteries

By contrast, a deep cycle battery is made for discharge and supports intensive cycling. It provides rechargeable power for many cycles, ideal for running electric outboard motors, trolling motors, and electronics onboard.

Compared with starting batteries, deep cycle batteries are more expensive and heavy, but they are perfect for powering stuff without an engine running.

Key takeaway:

Basically, the kind of battery you need for an outboard ultimately depends on your purpose.

If you’re looking for a battery for an electric start outboard motor (vs pull start) , the starting battery is what you want. However, if you own an electric outboard or trolling motor, you should use deep cycle batteries ( LiFePO4 is recommended).

4 Types Based on Chemistry

You will find four kinds of outboard motor batteries if you look at their chemistry inside the cells, namely flooded batteries, gel batteries, AGM batteries (advanced lead-acid batteries), and lithium batteries.

Among them, lithium is a HUGE upgrade in battery technology, and there are a great number of advantages that people run to lithium (especially LiFePO4) for their outboard motors:

You can fully discharge the battery cells every day (almost 100% vs 50% for AGM) without killing them. Moreover, they can recharge 2k-10k times vs 300-800 AGM.

These mean significantly more power capacity, so it can last twice as long on the water.

Not to mention they’re also a lot smaller and lighter than the comparable lead-acid battery, and charge much faster. And you can see the battery state on your phone or via a digital screen.

That’s why all reputable electric outboard motor brands, including ePropulsion , use lithium (or even LiFePO4) batteries as their accompanying batteries.

Further Reading : Why You Should Choose LiFePO4 Batteries

What size battery do I need for an outboard motor? What amp-hour rating should I get?

The electric outboard motor batteries are available in a variety of sizes and power levels.

Here is how to calculate the outboard battery sizes in simple steps:

Method #1. Start with Amps.

Step 1. Get the outboard motor electric consumption in Amps (usually available in the manual). Or calculate with Amps = Watts / Volts.

Step 2. Calculate the Amp hour rating of the outboard motor (Ah = Amps x Time).

This Ah rating indicates the battery size that will be sufficient for your requirements.

For example, if your motor consumes about 60 Amps and you want an outboard motor battery that will last 3 hours, you will need a 180 Ah ( = 60 Amps x 3 hrs) battery.

Method #2. Start with Wattage.

(Use this method if you know the wattage rating of your outboard motor.)

Step 1. Calculate the total watt required for the outboard motor battery (Wh = Watt x Time).

Step 2. Calculate the Ah rating with the given voltage (Ah = Wh / Volts).

For example, if you own a 1 kW outboard motor ePropulsion Spirit Evo and you want to use it for six hours on a 48V boat system (on a single charge), you will need a 125 Ah battery.

Note that the calculation is under full load and max amp draw (meaning you’re running the motor wide open the whole time).

In real life, the amp will be much less. That’s to say, you may get away with a smaller battery if you run at part throttle with intermittent use.

However, always go for a larger battery if you go with AGM/lead-acid deep cycle batteries.

Generally, you don’t want to discharge the battery more than 50% to prevent damage. So half the rated capacity.

Alternatively, lithium batteries can be more fully discharged without damage, so you can use more of the rated capacity, which is a big plus for outboard motor batteries.

Reading this far, I believe you should be able to decide the best outboard motor battery for your boat. If you are still not sure, here is a simple guide to help you make a quick decision.

Essentially, three things to consider:

If you are looking for a small outboard motor battery, the weight should be a top priority.

You will never want an outboard motor battery to sink your small boat and break your back every time you carry it from your car and to the dock.

In that case, the lightweight lithium battery would better fit your needs.

Typically, a 12V 100Ah lead acid battery weighs over 60 lbs. Comparatively, a 100Ah LiFePO4 battery weighs only 25 lbs. So you can easily shave about 35 lbs off the weight in your boat.

Not to mention its larger usable battery capacity and smaller lighter battery cell.

As a Zodiac boat owner reported, his 12V LiFePO4 outboard motor battery lasts 2 times as long as a 120 Ah lead acid that weighs 3 times what the LiFePO4 does.

#2. Battery Life

Outboard motor battery life should be a deciding factor in purchase decisions. You need to make sure the outboard motor battery gets enough juice to do the job.

So choose an outboard motor battery that comes with a larger battery capacity and longer life cycles. And the lithium battery goes a long way in these two aspects, with at least 80% DoD (depth of charge) and 5 times more charge cycles than lead-acid batteries.

However, how long your outboard motor battery can run actually depends on a lot more factors.

One of the key factors is outboard power. The best battery for an 25 HP outboard motor is definitely different from the one for 40 HP, since they are running at different watts.

For example, if your motor runs at 300W and you use it with a 230Wh LiFePO4 battery, you will get 40 to 50 minutes’ continuous usage out of this battery.

Note that throttle power settings also make a great difference in your outboard motor battery life:

When moving a boat through water in displacement mode, to go twice as fast you must increase the power about fourfold. That’s to say, if it theoretically takes 200W to go at 2 knots, it would take 800 watts to go at 4 knots.

At the same time, going at half throttle may quadruple your range, even though you’ll get there half as fast. Many electric boat owners simply go quite slowly to make the cost and physics add up.

Also, you can use a solar panel to help keep your outboard motor battery topped up.

Further Reading: Solar Powered Boat Motors: Easiest Way to Set up Your Solar Boat

The last step to get the best bang for your buck is to compare costs.

And that’s not all about the price tags.

Although the lithium outboard motor battery is more expensive, it can last 10+ years if taken care of properly.

Actually, it becomes cheaper if you plan to use it for many years. By this I mean that it may cost 2 times more upfront, but it will survive roughly 5 times as many cycles.

All in all, a lithium battery would be the best outboard motor battery option nowadays if you want to minimize size and weight and don’t mind a higher upfront cost.

Other than that, lead acid is also a reliable technology, proven and improved over hundreds of years. If you have a tight budget, go for a larger lead-acid battery.

How to wire an outboard motor to its battery?

In fact, it’s easy to hook up your outboard motor battery if you follow the manual. You don’t need to fumble with the outboard motor battery cables to get it plugged in.

Basically, you just need to connect the outboard motor and battery with the provided switch cable and communication cable. Also, the control system should be connected to the battery with communication cables.

Some small outboards come with an integrated battery, making it easy for the battery wiring.

For example, the 3 HP ePropulsion Spirit 1.0 Evo only requires you to place the battery in place (secured by two side slots), and then connect the power cable to the battery.

How to charge an outboard motor battery?

Generally speaking, an outboard motor battery needs to be charged with a specialized charger. And the charger decides the charging efficiency.

Fast chargers are available for some models, or you can also use two or more chargers in parallel connection to speed up the charging.

Does an outboard motor charge the battery itself?

Yes, most outboard motors can charge a battery directly while running just like your car’s motor can charge its battery:

The engines come with an alternator or generator. When you start the engine up, the engine will charge the starting outboard motor battery until full. If there is an aux battery, it will then switch over and charge the aux battery.

More About Outboard Motor Batteries

1. does an outboard motor need a battery.

Yes, your outboard motor will need a battery to work unless it’s a pull start.

2. Can a lithium battery start an outboard motor?

Standard deep-cycle lithium batteries are not designed for starter uses.

However, lithium batteries for starting outboard motors are now available, which are specially designed to meet the strict specifications for marine cranking use.

In fact, some outboard manufacturers, such as Mercury Marine, encourage users to use qualified lithium batteries to start the engine for optimal performance.

3. Does an outboard motor charge the battery when running?

Yes, you can charge a battery from an outboard by burning fuel. For electric outboards, some models (including ePropulsion Navy Evo ) can collect electricity from wind and water and charge themselves via a hydrogeneration function.

4. Can an outboard motor charge a lithium battery?

Unfortunately, most outboard motors can not charge a lithium battery directly. You will need a DC/DC charger to make it possible.

Other than that, you can invest in an electric outboard motor with hydrogeneration function which allows the motor to charge itself while sailing.

Hopefully, this post can help you clear your confusion about outboard motor batteries. If you have other concerns, please leave your question in the comment below and I will get back to you ASAP and add it to the list.

Recent Posts

ePropulsion Partners with 37th America’s Cup to Supply Sustainable Electric Power for Autonomous Race Marks

Why Do Boats Porpoise & How To Stop Your Boat From Porpoising

Join the discussion cancel reply.

Save my name, email, and website in this browser for the next time I comment.

Notify me via e-mail if anyone answers my comment.

This site uses cookies to personalize your experience and analyze site traffic. By clicking accept or continuing browsing the site, you are agreeing to our use of cookies. See our Privacy Policy here .

View the Serial Number

Please verify you are a human

Access to this page has been denied because we believe you are using automation tools to browse the website.

This may happen as a result of the following:

• Javascript is disabled or blocked by an extension (ad blockers for example)
• Your browser does not support cookies

Please make sure that Javascript and cookies are enabled on your browser and that you are not blocking them from loading.

Reference ID: abef6e35-63cd-11ef-be9e-7838eb7e750a

Powered by PerimeterX , Inc.

Practical Boat Owner

• Digital edition

Best boat battery: The pros and cons of the 5 different types of marine batteries

• Alison Wood
• October 28, 2022

Boats usually have two batteries (or banks of batteries) to ensure one is for starting the engine only, and the other to run the domestic systems.

Some marinas, such as Chichester Marina, require a key code for electrical supply. With others, shore power is included in the price

Sometimes (though not on Maximus ) there’s a third set of batteries for high power items such as a bow-thruster or electric windlass.

Wet lead acid

Batteries that have liquid electrolyte sloshing around in them are sometimes referred to as ‘wet’, ‘flooded’ or ‘wet lead acid’ batteries.

To start the engine, boats have a starting or ‘cranking’ battery, like those used in cars, which delivers very high loads for a few seconds.

Only a small portion of the battery’s capacity is used and this is restored by the alternator once the engine is running.

For powering everything else (i.e. chartplotter, lights, fridge, etc.) boats use a domestic, or ‘house’ deep-cycle (or deep-discharge/traction) battery bank which draws a much smaller amount of power over a longer period of time.

It’s important that wet lead acid batteries are stored in a ventilated area. A disadvantage is that they can ‘gas off’ (release hydrogen) if faulty, overcharged or getting old.

Pros: cheap, readily available, lots of choice, starter batteries can be bought in automotive stores. Cons: heavy, can leak, need regular charging, useless once flat, can gas off.

Article continues below…

Which battery is best for my boat? How to increase battery capacity on board

With more and more electrical gear going on board the modern cruising yacht there comes a time when the battery…

Lithium batteries vs lead-acid batteries: What are the key differences for boat owners?

But even the best lithium batteries do have downsides, writes Emrhys Barrell . The first is cost, at up to…

Wet lead acid – dual/leisure battery

An ‘in-between’ option is the ‘dual’ or leisure battery. A compromise between starting and deep-cycle batteries, these are popular on boats that carry only a single battery, or prefer to have the same type of battery for simpler charging.

Maximus had a leisure battery for starting the engine (an 85Ah Green Power) and a 100Ah deep-cycle Lifeline Battery for powering the rest of electrical equipment.

Both were flat after being left on board for two years and so could not be revived.

Pros: cheap, readily available, lots of choice, dual-purpose starter and domestic. Cons: heavy, can leak, need regular charging, useless once run flat, can gas off.

Rolls sealed VRLA deep cycle batteries on the Ecobat stand at Southampton Boat Show

Sealed lead acid batteries (gel & AGM)

Nobody wants battery acid leaking into the bilge, but there’s a price to pay if you want more durable batteries.

Sealed lead acid batteries are sometimes referred to as VRLA (valve regulated lead acid) and there are two main types – absorbed glass mat (AGM), where the battery plates are protected by fine-stranded glass mats – and gel, where the liquid electrolyte has been converted into a gel.

AGM batteries can be used for both starter and house applications whereas gel batteries are better suited for house applications only.

Both types can withstand many more charge/discharge cycles than conventional deep-discharge batteries – for example, a 7-10 year lifespan rather than a 4-5.

Pros: leak-proof, longer lifespan than wet lead acid, AGM can be dual-purpose starter and domestic. Cons: twice the price of wet lead acid, up to 25% heavier, need regular charging, useless once flat.

The extensive lead carbon battery bank for electric narrowboat Old Nick

Lead carbon batteries

Lead carbon batteries are not widely known. Our electrician had never fitted them, and indeed I hadn’t considered these until I spoke to Victron Energy.

However, they are highly regarded by PBO contributor Paul Sumpner, who fitted Leoch lead carbon batteries to his electric-propulsion narrowboat Old Nick .

Paul worked out his requirements, which were a regular DoD of 50%, year-round usage, a minimum of 48V, 600Ah, zero maintenance, a life cycle of 3,000+ discharges, non-vertical mounting and to be able to survive a regular partial state of discharge. Plus, they couldn’t “completely blow the budget”.

Old Nick , Paul Sumpner’s narrowboat, is electrically propelled and runs off lead carbon batteries.

“It became clear that only lead carbon or lithium batteries would be suitable,” he said, and later confirmed he couldn’t be happier with the equipment he chose.

Lead carbon batteries are an advanced type of VRLA battery, which has a positive plate (anode) of lead, but a negative (cathode) plate made of carbon composite.

According to Victron, the advantages are less sulfation, and a lower charge voltage, meaning higher efficiency and less corrosion of the positive plate. Overall, the result should be an improved cycle life.

Pros: leak proof, longer life, less sulfation. Cons: more expensive, can’t be used for starter motor, larger and heavier than AGM or lead acid.

AMPS 100Ah deep cycle lithium-ion battery

Lithium batteries

Lithium-ion is a broad chemistry of batteries, the most common being LiFePO4 (Lithium Iron Phosphate). They can withstand four or five times the number of cycles compared to most deep-cycle lead acid batteries (4,000+), can go down to a much lower state of charge, and can keep a reasonable level of charge for up to 12 months.

While lead acid batteries, in practice, only allow 30% of rated capacity, the best lithium batteries can be discharged to 70-80% of the rated capacity.

So really, a 100Ah lithium battery is the equivalent to having a 200Ah lead acid battery, only it will usually charge much quicker, is half the weight and a lot smaller.

A word of warning, though. Although lithium batteries can accept fluctuating voltage (13.6V-14.6V) like lead acid batteries, they should not be directly charged from an alternator because voltage spikes could damage them. A dedicated charger and battery management system is a necessity.

Pros: long-lasting, can use 80% of capacity, easier to manage, small, lightweight. Cons: expensive (up to 4 x cost of wet lead acid), boat adaptations required.

*Batteries chosen to show a range of brands and prices, not because PBO recommends these over others. Prices include VAT and UK delivery, and are taken from online retailers

Having had a brief look at batteries, I called marine surveyor Ben Sutcliffe-Davies. I wondered if there was any possibility of reviving flat batteries.

“I’ll be honest with you, start with new batteries,” he said. “You’re relying on this battery to start the boat. Yes it might pick up, but I guarantee it’ll be like a dying swan when you need it.”

The new batteries were fitted in a ventilated space below the cockpit

For domestic systems, Ben likes Numax batteries, which he says a lot of the industry use. For the cranker, he said, any automotive battery would do.

“I went down to my local tyre and exhaust place, and just got four heavy-duty deep cycle leisure batteries and one tidy cranker for the engine,” he told me.

Thanks to our Project Boat Supporters

Dell Quay Marine , Osculati , Raymarine , Shakespeare Marine , TruDesign , Screwfix , Coleman Marine Insurance , MDL Marinas , Premier Marinas , seajet , Marine & Industrial , Clean to Gleam , Dometic , West System , Farécla , Navigators Marine , Lewmar , RYA , Aqua Marine , Ecobat , Victron Energy , Scanstrut , T Sails and XP Rigging .

Why not subscribe today?

This feature appeared in the March 2022 edition of Practical Boat Owner . For more articles like this, including DIY, money-saving advice, great boat projects, expert tips and ways to improve your boat’s performance, take out a magazine subscription to Britain’s best-selling boating magazine.

Subscribe, or make a gift for someone else, and you’ll always save at least 30% compared to newsstand prices.

See the latest PBO subscription deals on magazinesdirect.com

Using A Solar Battery Charger for Your Boat

A reliable power source on board will keep all of the electronics running and maintain comfort out on the water. Traditional methods, such as generators, can be noisy, require fueling, and produce emissions. Solar battery chargers use a clean, renewable, silent alternative to run the electrical systems on your vessel. Choosing the right solar charger size by your specific power requirements is the key to fully harnessing the potential of your solar setup. Wrong estimates of your requirements can leave you with a totally drained battery, while an oversized system represents an extravagant investment. This guide will help you understand the different types of solar chargers and what to consider when selecting the ideal size for your boat.

What is a Solar Battery Charger?

A solar battery charger simply is a system that generates electrical energy from sunlight by solar panels and stores it away in rechargeable batteries for use at a time later. The main components necessary are solar panels, a battery bank, and a charge controller.

Solar panels are made of photovoltaic cells that absorb the sun's energy and then turn it into DC electricity. The more the panels are exposed to sunlight, the more electricity they produce. A battery bank is an energetically stored collection of deep-cycle batteries used to store the electricity generated by these solar panels. Since the deep cycle has the feature of repeated recharging and discharging, they are well adapted to be used in solar energy systems. A very important component functions in such a way that it regulates the flow of electricity from the solar panel to the batteries. The charge controller assures that the batteries remain free of any overcharge or overdischarge condition at their terminals that could spoil them and reduce their lifetime. The solar panels generate electricity when in the presence of solar. The generated energy is passed to the charge controller. It checks the battery charge level, and if not full, it sends the electricity to the batteries. When the batteries are full, the charge controller disconnects the flow of electricity to prevent overcharging the batteries.

Types of Solar Charging for Boats

There are three main types of solar charging systems suitable for boats, each designed to meet different power needs and usage patterns.

Trickle Solar Charging

Trickle solar charging systems are ideal for low-power electric boats that aren't frequently used. These compact and lightweight setups use smaller solar panels to slowly recharge your boat's battery over an extended period. Trickle chargers are a cost-effective solution for occasional boaters who don't require high power output but want to maintain their battery's charge level.

Light-Use Solar Charging

Light-use solar chargers are perfect for powering small electronics like phones, tablets, cameras, and other gadgets while on the water. These systems typically feature portable solar panels with modest wattage ratings, allowing you to charge devices directly or top up a power bank for later use. Their compact size and portability make them a convenient choice for day trips or short excursions.

Heavy Power-Use Solar Charging

For luxury yachts, houseboats, or frequently used boats with high power demands, heavy power-use solar charging systems are the way to go. These robust setups incorporate high-capacity solar panels and large power stations or solar generators to provide ample electricity for running appliances, entertainment systems, and other energy-intensive equipment. Heavy power-use systems can generate and store enough energy to keep your boat fully powered without relying on noisy generators or draining your main battery.

Trickle solar charging is ideal for low-power electric boats that are not frequently used. These systems are designed to slowly charge your boat's battery over an extended period, providing just enough power to maintain the battery and prevent it from draining completely.

Trickle solar chargers typically consist of a small solar panel, often ranging from 5 to 20 watts, and a basic charge controller. The solar panel converts sunlight into electrical energy, which is then regulated by the charge controller to safely charge the battery without overcharging it.

These systems are lightweight, compact, and relatively inexpensive, making them a convenient choice for small boats or those used occasionally. However, it's important to note that trickle solar chargers are not suitable for powering electrical appliances or providing significant amounts of energy. Their primary purpose is to maintain the battery's charge level during periods of inactivity or storage.

When selecting a trickle solar charger, consider the size of your boat's battery and the amount of sunlight exposure it will receive. Larger batteries may require a slightly higher wattage solar panel to ensure adequate charging. Additionally, if your boat is stored in a shaded area, you may need to adjust the panel's positioning or opt for a more powerful system to compensate for the reduced sunlight exposure.

For boaters looking to power small electronics like phones, tablets, and cameras, a lightweight and compact solar charger is an ideal solution. These portable solar panels are designed to be easily transported and set up, providing a reliable source of power while on the water.

Light-use solar chargers typically range from 10 to 50 watts, with panel sizes varying from the size of a tablet to a small briefcase. Despite their compact size, these chargers can efficiently convert sunlight into electricity, making them perfect for keeping your devices charged and ready for use.

One of the key advantages of light-use solar chargers is their portability. Many models fold up into a compact shape, making them easy to store and transport. Some even come with built-in kickstands or mounting options, allowing you to position the panels for optimal sun exposure while on your boat.

When choosing a light-use solar charger, consider the output voltage and amperage, as well as the number of USB ports or other charging options. Look for panels with high-efficiency solar cells and durable construction to withstand the marine environment. Additionally, some models come with built-in batteries or power banks, providing a convenient way to store energy for later use.

With a light-use solar charger on board, you can keep your essential electronics powered up without relying on your boat's main battery or noisy generators. This not only adds convenience but also contributes to a more sustainable and eco-friendly boating experience.

For boaters with high power needs, such as those with luxury yachts equipped with TVs, coffee makers, and other energy-intensive appliances, heavy power-use solar charging systems are the ideal solution. These systems utilize solar generators capable of delivering substantial amounts of electricity without the noise and emissions associated with traditional generators.

At the heart of a heavy power-use solar charging system is a high-capacity power station or solar generator. These units typically feature large lithium-ion battery packs with capacities ranging from 1,000 to 3,000 watt-hours or more. This stored energy can then be converted into AC power, providing a steady supply of electricity for your boat's appliances and electronics.

To keep these power stations charged, they are paired with multiple high-efficiency solar panels. These panels are designed to capture as much of the sun's energy as possible, often boasting conversion rates of 20% or higher. By connecting several panels in an array, a significant amount of power can be generated, even on partly cloudy days.

One of the key advantages of heavy power-use solar charging systems is their ability to deliver sustained high power output. Many solar generators are capable of producing up to 2,000 watts or more of continuous AC power, rivaling the output of a traditional gasoline generator. This level of power ensures that even energy-hungry appliances can be run without issue, allowing you to enjoy all the comforts of home while out on the water.

Key Components of a Boat Solar Charger

When setting up a solar battery charger system for your boat, there are four key components you'll need:

Solar Panels

The solar panels are the heart of the system, converting the sun's energy into electricity to charge your batteries or power devices directly. Look for solar panels with high efficiency ratings, as this will determine how much power they can generate from the available sunlight. Monocrystalline panels tend to be more efficient than polycrystalline, but also more expensive. Make sure the panels you choose are designed for marine use and can withstand exposure to salt water.

Power Station

A power station , or solar generator, acts as a battery pack to store the electricity generated by your solar panels. This allows you to have power available even when the sun isn't shining. Capacity is an important consideration - the higher the capacity, the more appliances and devices you'll be able to run. Also look at the AC and DC output ratings to ensure compatibility with your boat's power needs.

Proper wiring is critical for safely connecting the solar panels to the power station and any devices or batteries you want to charge. Use marine-grade wiring rated for outdoor use and sized appropriately for the expected electrical load. Consider factors like cable length and include components like fuse blocks to protect against shorts or overloads.

Charge Controller

A charge controller manages the flow of electricity from the solar panels to your batteries, preventing overcharging which can damage the batteries over time. Look for MPPT (Maximum Power Point Tracking) controllers which are more efficient than simple PWM versions. Make sure to match your controller with the voltage of your battery bank and solar array.

With the right combination of high-quality components sized for your specific boating needs, a solar charger system can keep your batteries topped up and provide reliable power while out on the water.

Choosing the Right Solar Panels

Selecting the right solar panels is crucial for ensuring your solar battery charger system functions efficiently on your boat. When it comes to solar panels, two key factors to consider are conversion efficiency and wattage output.

High conversion efficiency is essential as it determines how much of the sun's energy can be transformed into usable electricity. Look for solar panels with efficiency ratings of 20% or higher, as this will maximize the amount of power you can generate from a limited surface area on your boat. Top-tier solar panels like monocrystalline options can achieve efficiencies upwards of 23%, making them an excellent choice for marine applications.

The wattage output of your solar panels will dictate how much power your system can produce. This is directly tied to the size and number of panels you install. Larger panels with higher wattage ratings will generate more electricity, but they also take up more space on your boat. Assess your power needs and available deck space to determine the appropriate wattage for your setup. A common range for boat solar panels is 100 to 400 watts per panel.

In addition to efficiency and wattage, consider factors like durability, weatherproofing, and portability when selecting solar panels for your boat. Marine-grade panels designed to withstand harsh conditions and saltwater exposure are ideal. Flexible, lightweight options can also be advantageous for easy installation and portability between vessels.

Selecting a Power Station

The power station is a crucial component of your boat's solar battery charger system, as it stores the energy generated by the solar panels and provides an efficient output for powering your electrical devices. When choosing a power station, consider the energy storage capacity and output needs to ensure it can handle your boating activities.

Energy storage capacity is measured in watt-hours (Wh) and determines how much power the station can hold. A higher capacity means you can run more devices for longer periods without recharging. For light use, such as charging phones and tablets, a lower capacity of around 200-500Wh may suffice. However, if you plan to power larger appliances like TVs, coffee makers, or even a small refrigerator, you'll need a higher capacity power station, typically ranging from 1000Wh to 2000Wh or more.

The output wattage is another important factor, as it determines the power the station can deliver to your devices. A higher output wattage allows you to run more power-hungry appliances simultaneously. Most power stations offer output wattages between 200W and 2400W, with higher-end models capable of delivering up to 4000W or more.

Portability is also a consideration, especially for smaller boats or kayaks. Look for compact and lightweight power stations that are easy to transport and store. Many models come with carrying handles or wheels for added convenience.

Remember to choose a power station compatible with your solar panels and other components, ensuring efficient energy transfer and safe operation. Reputable brand like Growatt offer a wide range of power stations suitable for various boating needs.

Wiring a Boat Solar System

Proper wiring is crucial for efficiently connecting the solar panels, charge controller, and battery bank in a boat solar system. The gauge or thickness of the wires used will determine how much electrical current can flow through them without significant power loss or risk of overheating.

When selecting wire gauge, consider the distance the wires will run and the maximum current they will carry. Longer runs and higher currents require thicker wires to minimize voltage drop. For example, a common setup uses 10 AWG wire for shorter runs from the solar panels to the charge controller, and 6 AWG wire for longer runs between the charge controller and batteries.

All wiring used in a marine environment should be outdoor-rated and UV-resistant to withstand the harsh elements. Tinned marine-grade wire is ideal as it resists corrosion from salt water and moisture. Solid or stranded wire can be used, but stranded is more flexible for routing through tight spaces.

A typical wiring diagram has the solar panels wired in series using MC4 connectors, which feed into the charge controller. From the controller, heavy gauge wires run to the battery bank, with a fuse or circuit breaker inline for safety. The entire system should be properly grounded, and all connections must be waterproof and secure to prevent hazards.

Using a Charge Controller

A charge controller is a crucial component in a solar battery charger system for boats. Its primary function is to regulate the power flowing from the solar panels to the batteries, preventing overcharging and potentially damaging the batteries.

When the batteries are fully charged, the charge controller stops or reduces the flow of electricity from the solar panels. This helps extend the lifespan of the batteries and ensures they are not subjected to excessive charging, which can lead to overheating, gas buildup, and potential explosions.

Charge controllers also play a vital role in ensuring compatibility between the various components of the solar system. They match the voltage and current requirements of the solar panels, batteries, and any other connected devices. This compatibility is essential for efficient energy transfer and optimal system performance.

When selecting a charge controller, it's important to consider factors such as the maximum input voltage from the solar panels, the battery voltage, and the maximum charging current required. Additionally, charge controllers come with different features like temperature compensation, load control, and monitoring capabilities, which can enhance the overall functionality and efficiency of the system.

By incorporating a charge controller into your boat's solar battery charger setup, you not only protect your investment but also ensure a safe and reliable flow of power, maximizing the potential of your solar energy system while on the water.

Benefits of Solar for Boaters

Solar battery chargers offer several key advantages for boaters looking to power their electronics and appliances on the water. Firstly, solar energy is a completely renewable resource, harnessing the power of the sun's rays to generate electricity. This means you can keep your batteries charged without consuming any fossil fuels, making solar an environmentally-friendly choice.

Another major benefit is that solar charging systems operate silently. Unlike noisy generators, there are no moving parts or combustion processes involved. This allows you to enjoy the peace and tranquility of being on the water without disruptive engine noise.

Solar battery chargers also require very little maintenance compared to traditional charging methods. There are no fuel filters to replace or oil to change. As long as the solar panels are kept clean and free of debris, the system will continue to function efficiently with minimal effort.

Perhaps the biggest draw for many boaters is the increased comfort and convenience that solar power provides. With a properly sized solar setup, you can run lights, electronics, small appliances and more without worrying about draining your boat's primary battery bank. This allows you to extend your time on the water and enjoy amenities like you would at home, all powered by clean, quiet solar energy.

Cost Savings with Solar

One of the primary benefits of installing a solar battery charger on your boat is the potential for significant cost savings over time. By harnessing the free and renewable energy from the sun, you can drastically reduce or even eliminate your reliance on traditional fuel sources or shore power hookups.

For boats that primarily rely on gasoline or diesel generators for electricity, the fuel costs can quickly add up, especially during extended trips or periods of heavy usage. A solar battery charger system can provide a clean and cost-effective alternative, allowing you to power your boat's electrical systems without the need for fuel. Even if you only use solar power as a supplemental source, the savings on fuel can be substantial over the course of a boating season.

Similarly, for boats that typically rely on shore power when docked, the costs of marina fees and electricity hookups can also be significant. With a solar battery charger, you can potentially reduce or eliminate these costs, as your boat's batteries can be recharged directly from the sun while docked or anchored.

While the initial investment in a solar battery charger system can be considerable, depending on the size and components required, the long-term cost savings can often offset this expense within a few years. Many boat owners find that the system pays for itself through reduced fuel and electricity costs, making it a wise investment for both financial and environmental reasons.

It's important to note that the payback period for a solar battery charger system can vary depending on factors such as your boat's energy consumption, the amount of sunlight available in your boating area, and the efficiency of the components you choose. However, with proper planning and system sizing, most boat owners can expect to recoup their investment within a reasonable timeframe, typically ranging from 3 to 7 years.

Sizing Your Solar Battery Charger System

Properly sizing your solar battery charger system is crucial to ensure it meets your boat's energy needs. The first step is calculating your power requirements by listing all the electrical devices and appliances you'll be running and their respective wattages. Don't forget to account for the operating time of each device.

For example, a TV drawing 150 watts used for 4 hours per day would require 600 watt-hours (150W x 4 hours). Make a comprehensive list, adding up the watt-hours to determine your total daily energy needs.

Next, you'll need to match your energy needs to the components of your solar system. The solar panels should have enough capacity to generate the required watt-hours, factoring in real-world conditions like cloudy days. As a rule of thumb, look for panels rated at least 25% higher than your calculated needs.

The power station or battery bank must have sufficient capacity to store the energy generated by the solar panels. Its watt-hour rating should exceed your daily load to allow for energy reserves. Most systems work best with 2-3 days' worth of battery storage.

Finally, ensure the charge controller is compatible with both your solar panels and battery bank, able to handle the maximum voltage and current. Oversizing the controller slightly provides a buffer for future expansion.

Taking the time to properly calculate your sizing needs upfront leads to a well-matched, efficient solar battery charging system tailored to your boat's unique power demands.

Installation and Safety

Proper installation of a solar battery charger system on your boat is crucial for ensuring optimal performance and safety. The marine environment presents unique challenges, such as exposure to saltwater, moisture, and potential corrosion, which must be addressed during the installation process.

When installing solar panels, it's essential to choose a location that maximizes sun exposure while considering the boat's stability and weight distribution. Proper mounting techniques, including the use of marine-grade hardware and sealants, are necessary to withstand the harsh conditions at sea. Additionally, solar panels should be positioned to avoid shading from the boat's superstructure or other obstructions.

Wiring plays a vital role in the solar charging system, and it's essential to use marine-grade cables designed to withstand the elements. Proper cable sizing is crucial to minimize voltage drop and ensure efficient power transfer. All connections should be waterproofed and secured to prevent chafing or damage from the boat's movement.

The power station and charge controller should be installed in a dry, well-ventilated area, protected from direct exposure to the elements. Proper grounding and fusing are essential for safe operation and to prevent electrical hazards.

Safety should be a top priority when working with electrical systems on a boat. Always follow the manufacturer's instructions and consult with a professional if you're unsure about any aspect of the installation. Wear appropriate personal protective equipment, such as gloves and safety glasses, and exercise caution when handling batteries and electrical components.

It's also essential to consider the potential for electrical interference with other onboard systems, such as navigation equipment or radios. Proper shielding and grounding techniques may be necessary to minimize interference and ensure the safe operation of all systems.

Regular maintenance and inspection of the solar charging system are crucial to ensure its continued safe operation. Check for any signs of wear, corrosion, or damage, and address any issues promptly to prevent potential hazards or system failures.

Maintaining Your Solar Battery Charger System

Proper maintenance is key to ensuring your boat's solar battery charger system operates efficiently and has a long lifespan. Here are some important maintenance tips:

Cleaning Solar Panels

Over time, dirt, bird droppings, and other debris can accumulate on the solar panels, reducing their ability to absorb sunlight and generate power. Clean the panels regularly with a soft brush and mild soap solution to remove any buildup. Avoid using harsh chemicals or abrasives that could damage the panel surface.

Battery Maintenance

The battery bank is the heart of your solar charging system, storing the energy generated by the solar panels. Check the battery's water levels periodically (if using lead-acid batteries) and top up with distilled water if needed. Inspect the battery terminals for corrosion and clean them if necessary. Consider investing in a battery monitor to track the battery's state of charge and overall health.

System Checks

Regularly inspect the entire solar charging system for any signs of damage, loose connections, or wear and tear. Check the wiring for any fraying or damage, and ensure all connections are tight and secure. Inspect the charge controller for proper operation and verify that it's correctly regulating the flow of power from the solar panels to the battery bank.

Seasonal Maintenance

Depending on your location and boating season, you may need to take additional steps to prepare your solar charging system for winter or extended periods of non-use. This could include disconnecting the batteries, covering the solar panels, or storing components in a dry, protected area.

By following these maintenance practices, you can help ensure your boat's solar battery charger system operates reliably and efficiently, providing you with clean, renewable power for years to come.

Solar battery chargers are great for boaters who need an able, eco-friendly, and cost-effective power solution. With solar power harnessed from the sun, you derive pleasure from the great convenience energy source that is free for recharging your boat's electronics, appliances, and systems, all without the noise from a generator or worry over the cost of fuel. Selecting the right size of solar charging battery is of utmost importance because the right power is crucial for the total fulfillment of the boating requirement. Whether you need part-time trickle charges or heavy-duty solutions for luxury yachts, solar charging solutions are customized for your needs. Proper sizing would not only provide the proper power but would not also waste space and weight on your vessel. As the world shifts towards the adoption of sustainable sources of energy, the future of solar boating seems very bright. Solar panel potential and advanced battery technology will hold much in the way of promise for sailing boat owners in the near future. Not only is it environmentally friendly, but it also raises the level of your boating experience way higher, allowing you to cruise silently, cleanly, and independently.

Shop a  solar battery charger at Growatt today!

• 1382Wh Capacity & 1800W Output
• LiFePO4 Battery with 3,000+ Life Cycles to 80%
• Fully charged in 1.8 hours
• Up to 14 Versatile Outlets

Greeting Guys!!!

Special coupon for all HOBO Fans here in Growatt.

*Your personal data will not be shared with any third-party companies. For more details, please check the Growatt privacy policy.

FREE SHIPPING on most orders of $35+ & FREE PICKUP IN STORE

Shop by Category

Don't see the part you searched for.

Search your part number using our part interchange & find interchangeable parts for your application.