14 Best Marine Batteries (Starting, Deep Cycle & Dual-Purpose) For Boats In 2019

You will need a suitable battery for your maritime vehicles. The best marine battery allows your boat’s system to function at its most efficient.

A good marine battery not only essential to start and to power up a boat but also provide quality performance as well as a longer lifespan.

In this guide, we have looked into hundreds of marine batteries for boat and select only the best to be included in the marine battery reviews below.

Some of the batteries we’ve listed below are dual-purpose batteries too.

These dual-purpose batteries are designed to both crank an engine and for use as a deep cycle power source for trolling motors, electrical equipment, and appliances.

So, on this page, we’ll explore:

Also, if you want to know more about automotive batteries, check out these articles – Best Car Battery, How to Recondition Batteries and How Long Does Car Battery Last.


Discover the Best Marine Battery to Use on Your Boat

So, how do you go looking for the best boat battery for your water-based vehicle?

Start with marine battery reviews like this article of course. There are many types of marine batteries to choose from, as well as many places to buy them too.

You can buy them in your local auto shops or browse online in stores like Amazon and Autozone.

All of our top recommendations include information on each battery’s cranking power and reserve capacity.

We’ve also included detailed reviews of each battery that go into more detail about its specific strengths, weaknesses and unique features.

Let’s continue reading below.


Best Boat Battery – Reviews

Best Overall Pick
Universal Power Group 12V 100Ah Solar Wind AGM SLA DEEP Cycle VRLA Battery 12V 24V 48V
Best Premium Pick
Vmaxtanks VMAXSLR125 AGM 12V 125Ah SLA Rechargeable Deep Cycle Battery for Use with Pv Solar Panels...
Best Budget Pick
Interstate Batteries 12V 35Ah Deep Cycle Battery (DCM0035) Rechargeable Replacement Mobility Battery...
Universal Power Group 12V 100Ah Solar Wind AGM SLA DEEP Cycle VRLA Battery 12V 24V 48V
Vmaxtanks VMAXSLR125 AGM 12V 125Ah SLA Rechargeable Deep Cycle Battery for Use with Pv Solar Panels...
Interstate Batteries 12V 35Ah Deep Cycle Battery (DCM0035) Rechargeable Replacement Mobility Battery...
• The battery is valve regulated • It is maintenance free • Leak and spill-proof • Its AGM design provides perfect deep cycle performance rating • It has less than 3 percent per month standing self-discharge
• The battery has a long life • Has a low self-discharge rate when used in stand mode for power backup • Has a solid and robust construction • Designed with military grade custom plates
• Provides dependable power for different applications • Lightweight for easy handling • You can mount it any angle because it is spill proof • No need of maintenance
Complaints of the battery not holding charge
Stops holding charge after a few weeks of using
The battery is small. Might not suitable for all vehicles
Best Overall Pick
Universal Power Group 12V 100Ah Solar Wind AGM SLA DEEP Cycle VRLA Battery 12V 24V 48V
Universal Power Group 12V 100Ah Solar Wind AGM SLA DEEP Cycle VRLA Battery 12V 24V 48V
• The battery is valve regulated • It is maintenance free • Leak and spill-proof • Its AGM design provides perfect deep cycle performance rating • It has less than 3 percent per month standing self-discharge
Complaints of the battery not holding charge
Product Reviews
Best Premium Pick
Vmaxtanks VMAXSLR125 AGM 12V 125Ah SLA Rechargeable Deep Cycle Battery for Use with Pv Solar Panels...
Vmaxtanks VMAXSLR125 AGM 12V 125Ah SLA Rechargeable Deep Cycle Battery for Use with Pv Solar Panels...
• The battery has a long life • Has a low self-discharge rate when used in stand mode for power backup • Has a solid and robust construction • Designed with military grade custom plates
Stops holding charge after a few weeks of using
Product Reviews
Best Budget Pick
Interstate Batteries 12V 35Ah Deep Cycle Battery (DCM0035) Rechargeable Replacement Mobility Battery...
Interstate Batteries 12V 35Ah Deep Cycle Battery (DCM0035) Rechargeable Replacement Mobility Battery...
• Provides dependable power for different applications • Lightweight for easy handling • You can mount it any angle because it is spill proof • No need of maintenance
The battery is small. Might not suitable for all vehicles
Product Reviews

What is the best battery for a boat?

Well, the most straightforward answer would be to get a durable marine battery from one of the top brands.

Now, if you’re not the type who likes to read through reviews but want to know which is the best boat battery quickly, then we’d like to recommend the above three best pick.

But, if you want to consider all the purchasing options carefully, there are many types you can choose. Here are some of the best marine battery for you to check out:

#1. Vmaxtanks SLR-125 125Ah AGM

Vmaxtanks VMAXSLR125 AGM 12V 125Ah SLA Rechargeable Deep Cycle Battery for Use with Pv Solar Panels...
  • 12 Volt 125Ah Group 31 AGM Deep Cycle Heavy...
  • Military grade custom made plates
  • Float service life span of 8 to 10 years
  • Designed for 99% recombination capabilities;...

If you’re looking for the best deep cycle marine battery, one of your sure options is this battery.

The Vmaxtanks SLR-125 is a 12V with 125Ah battery. Also, this AGM battery is made for heavy-duty use.

This battery created to be high performing and durable with its military-grade custom plates in place. It’s designed to give off zero fumes and gases that can be dangerous to your health.

Plus, its float service can last for up to 10 years.

The Vmaxtanks SLR-125 is a good battery to consider when you want to replace your old one.


#2. Interstate DCM0035 35Ah Sealed Lead Acid AGM

Interstate Batteries 12V 35Ah Deep Cycle Battery (DCM0035) Rechargeable Replacement Mobility Battery...
  • DCM0035 BATTERY REPLACEMENTS: Compatibility...

An expensive price tag isn’t the basis for how great a battery can perform. This battery from Interstate proves that.

This non-lithium deep cycle battery is highly dependable and is known for giving excellent service to its users.

It lasts for a very long time and is one of the most affordable batteries out there today.

You can use it for a ton of applications like both ground and water vehicles, farming equipment, lighting, and even medical machines.

Indeed, this battery is one of the best marine battery in the market.


#3. Mighty Max ML55-12 55Ah Electric Trolling Motor

12V 55Ah Power Boat Pontoon Electric Trolling Motor Deep Cycle Battery
  • ML55-12 SLA is a 12V 55AH Sealed Lead Acid...
  • Dimensions: 9.06 inches x 5.43 inches x 8.98...
  • SLA / AGM spill proof battery has a...
  • Rechargeable battery that can be mounted in...

This 12-volt 55Ah deep cycle battery is rechargeable and maintenance-free. Of course, that doesn’t mean you don’t need to do regular maintaining.

However, if you want less hassle, then this battery is perfect for you. It’s spill-proof, and you can mount it in any position.

This AGM battery has a high discharge rate, great recovering capacity, and can resist shocks and vibrations.

It can even perform well in different temperatures, both high and low.

Plus, it has an impressive full one-year warranty.


#4. Universal UB121000 100Ah Deep Cycle AGM

Universal Power Group 12V 100Ah Solar Wind AGM SLA DEEP Cycle VRLA Battery 12V 24V 48V
  • UPG #45978 UB121000 12V 100Ah
  • Dimensions: 12.17 inches x 6.61 inches x 9.16...
  • SLA/AGM maintenance free, spill proof battery
  • Rechargeable battery that can be mounted in...

This deep cycle battery is another fantastic choice to look into. At 12-volts with 100Ah, it provides a powerful service to your marine vehicle.

The Universal UB121000 is also spill-proof, and maintenance-free so you don’t need to put too much effort into its care.

You can mount it in any type of position which is beneficial if you have a non-regular hood.

It can even resist both shocks and vibration and comes with an excellent one-year warranty.


#5. Odyssey 31 PC2150S 100Ah Heavy Duty

ODYSSEY 31-PC2150S Heavy Duty Commercial Battery
  • Longer cycle life: 70 percentage longer cycle...

This battery from Odyssey has a CCA of 1150 which makes it highly tolerant in terms of temperatures. It can work well even during extremely cold and hot weather.

The Odyssey PC2150S also has a longer cycle life than most deep cycle batteries. In fact, it lasts longer than 70% of batteries in the market today.

Also, not forgetting to mention that you can recharge your battery super fast. In just 4 to 6 hours, your battery rate can reach 100%.

Plus, this battery brand has an excellent warranty deal: a limited 3 and 4-year full replacement warranty.


#6. VMAX MR127 100Ah AGM

VMAX MR127 12 Volt 100Ah AGM Deep Cycle Maintenance Free Battery Compatible with Boats and 40-100lb,...
  • 12 Volt 100Ah Group 27 Deep Cycle Heavy Duty...
  • Electrolyte Suspension system VMAX tanks...
  • Heavy Duty Grids: VMAX heavy duty lead tin...
  • Fits any Group 27 Battery Box, fits the...

This 12-volt 100Ah deep cycle battery powerhouse from VMAX is highly durable and heavy duty.

It uses an electrolyte suspension system that consists of AGM technology that completely absorbs and contains the electrolyte.

The VMAX MR127 is maintenance-free so you won’t need to put a lot of effort into a routine. Also, it’s made from sturdy material like the heavy duty lead-tin alloys used as grids.

Best of all, it has very convenient carrying handles for easy installation and replacement.


#7. Optima 8016-103 D34M 12V 55Ah Marine Battery

Optima OPT8016-103 Batteries D34M BlueTop Starting and Deep Cycle Marine Battery
  • 12-Volt, 750 Cold Cranking Amps, Size: 10...
  • Optimal starting power even in bad weather
  • Mountable in virtually any position. Works...
  • Fifteen times more resistant to vibration for...

The Optima Deep Cycle 8016-103 D34M BlueTop has 750 cold cranking amps rating. And, this battery is an excellent starter battery for boats, RVs, and mechanical equipment.

At 750 CCA, this marine battery will perform well in the cold weather and it can withstand vibration well due to AGM technology.

Also, this battery has 120-minute reserve capacity, giving it a sufficient amount of reserve storage for use with a trolling motor.

The battery comes with a 2-year warranty as well.


#8. EXIDE XMC-31 12V 100Ah Sealed AGM Marine Battery

Exide XMC-31 MEGACYCLE AGM-200 Sealed Maintenance Free (AGM) Marine Battery
  • 925 CCA at 0 degrees F, 1110 CA at 32 degrees...
  • 200 minute reserve capacity
  • Dual terminal design
  • Absorbed glass mat separator is engineered...

The Excide XMC-31 is designed to charge quickly and can retain more power if compared to its similar class from other battery brands.

This battery is built with strong exterior housing keeps this battery safe and protected, with excellent resistance to vibration and wear.

It also uses the AGM technology to prevent the battery from drying and it’s maintenance-free.

Also, this battery can last for 200 minutes of regular use (25-amp continuous draw at a temperature of 80°F).

Best of all, the Excide XMC-31 comes with a 24-months warranty.


#9. Optima Batteries 8027-127 D27M 12V 66Ah Starting and Deep Cycle Marine Battery

Optima Batteries 8027-127 D27M BLUETOP Starting and Deep Cycle Marine Battery
  • Pure lead spiralcell design allows for lead...
  • Spiralcell technology for superior vibration...
  • Solid cast cell connections for increased...
  • Tightly compressed cells for added vibration...

The Optima 8027-127 D27M utilizes a pure lead spiral design that allows the lead to be used in its pure form, hence, better performance.

This spiral makes the battery resistant to vibration hence extending its life.

Also, this battery has solid cast cell connections that provide increased durability and maximum plate height.

The standard voltage of the battery is 12 Volts. When the battery fully charged, the voltage can go up to 13.5 Volts.

It also has a reserve capacity of 140 minutes which can be excellent for deep cycling and powering trolling motors.

The Optima 8027-127 D27M uses AGM technology hence making it completely maintenance free.


#10. Vmaxtanks MR107 12 Volt 85Ah Absorbed Glass Mat

VMAX MR107-85 12V 85AH AGM Deep Cycle Marine Battery Compatible with 12 Volt 55 Pound 55lb Thrust...
  • ESTIMATED RUN TIME: The MR107 will power a...
  • 12V 85Ah; Reserve Capacity: 160min ;...
  • Maintenance Free Operation: There is no need...
  • Rechargeable Sealed battery resists shocks...

The Vmaxtanks MR107 Deep Cycle Battery is a 12 Volt marine battery, maintenance-free and can re-charge very fast.

It is capable of delivering up to 85Ah in a single charge, enough for a more reliable and effective machine-starting experience.

It also comes with a carry handle that makes carrying and replacing the battery easily from your boat.

Best of all, this battery provides strong power for deep cycling and is built for heavy-duty use.


Best Dual Purpose Marine Battery

Now, if you have limited space on your battery compartment and unable to install multiple batteries, then look for a dual purpose marine battery.

This type of battery can serve both as starting the engine and powering up electronic devices and appliances on the boat.

Some of the more famous battery brands for dual purpose are like Optima and Odyssey. Here are some of the best choice:

#11. Optima YellowTop Batteries 8040-218 D35 Dual Purpose Marine Battery

Optima Batteries OPT8040-218 D35 YellowTop Dual Purpose Battery
  • 12-Volt, 650 Cold Cranking Amps, Size: 9...
  • 98 minutes reserve capacity for constant...
  • Optimal starting power even in bad weather;...
  • Fifteen times more resistant to vibration for...

The Optima YellowTop Batteries 8040-218 D35 is one of the best dual purpose marine battery 12 Volt marine battery and has 650 cold cranking amps.

This makes it a powerful battery for starting small to medium sized outboard motor. It can be used as a starting and trolling battery to kick start your boat and provide electricity to your appliances and gadgets.

What’s nice about this model is that it’s small and lightweight making it very portable. Perfect if your boat or cars has only limited space in the battery compartment.

Also, this battery has a reserve capacity of 98 minutes which is an excellent choice for powering smaller trolling motors.

This battery made with AGM technology and came with a 36-months warranty.


#12. Optima Batteries 8052-161 D31M

Optima Batteries 8052-161 D31M BlueTop Starting and Deep Cycle Battery
  • 12-Volt, 900 Cold Cranking Amps, Size: 12...
  • Reserve capacity of 155 minutes for constant...
  • Optimal starting power even in bad weather;...
  • This item is not for sale in Catalina Island

The Optima 8052-161 D31M is another top dual purpose marine battery that most marine vehicle owners go after.

This marine battery has 900 CCA and 1000Ah marine cranking amps which make it a powerful battery for starting outboard motors and other demanding equipment.

This battery has a 155-minute reserve capacity at 80°F and 25 amps, giving it ample power for deep cycling and powering trolling motors.

Also, the thick and solid and durable plastic exterior can withstand constant vibration without any problem.

This Optima 8052-161 D31M comes with a 2-year warranty.


#13. Odyssey 31M Trolling Thunder Dual Purpose

Odyssey 31M-PC2150ST-M Trolling Thunder Marine Dual Purpose Battery
  • Cold Crank Amp (CCA)- 1150 Better warranty:...
  • Longer cycle life: 70 percentage longer cycle...
  • Recharge: Highest recharge efficiency of any...
  • Vibration resistance-design protects against...

The Odyssey Extreme Series are some of the very best dual purpose marine batteries in the market right now.

While the price can be at the higher end,  but not many AGM batteries can offer such good specs or as good a warranty when comparing to Odyssey 31M.

To have a quick look at the spec, this marine battery has a reserve capacity of 205 minutes and capacity rating of 100 Amp hours. The CCA is 1150 Amp which considered very high.

As for the weight, it’s 77.8-pounds and the size is a group 31.

The excellent reserve power and capacity rating provides sufficient power for fishing boat with several large fish finders, plus other appliances.

Also, the high 1150 CCA is powerful enough to crank the bigger 200-250hp engine without breaking a sweat.

The conclusion is if you are looking for the best dual purpose marine battery, you can expect the Odyssey 31M battery to perform exceptionally well for your marine vehicles.


#14. Trojan 27-AGM Dual Purpose AGM

Trojan T27-AGM 12V 89Ah Group 27 Dual Purpose Deep Cycle Battery
  • Voltage: 12, Amperage: 89mAh, Chemistry: AGM
  • Length: 12.000, Width: 6.600, Height: 8.100
  • Group 27

Another excellent but lesser known dual purpose deep cycle battery is the Trojan. Trojan batteries brand has a long history of producing quality batteries. Each of their batteries built to last long as their batteries are eco-friendly too.

The Trojan 27-AGM has 158 minutes of reserve power, capacity rating of 89 Amp hours and CCA of 550.

Trojan AGM battery contains a high-density paste formula that is designed specifically for high-performance batteries to offers a longer run time than most of their competitors and lowers the operating costs associated with the battery.

Also, the Trojans grid technology provides a structurally sound battery that reduces the risk of corrosion and deterioration of parts.

This marine battery weight 64-pounds and is a group 27 battery.


How to Choose the Best Marine Battery


Marine batteries can vary hugely in quality and performance.

Therefore, it’s essential to be aware of the key features of a good battery before you make a purchase.

Not only does it [marine battery] have to offer high cranking amps to start up your boat’s engine, but it also has to have significantly more slow discharge power, in order to successfully supply energy not only for lights and sound systems, but for lighting and any important equipment required to ensure the safety of the crew during travel. – Advance Auto Parts

There are a few factors you might want to consider when buying your marine battery.

Some of these factors are listed below:

  • Starting & Cold Cranking Amps (CCA)

CCA or MCA (Marine Cranking Amps) determine your battery’s capability to provide power during a short period.

It is an exact measurement of the amount of electrical power a battery’s lead-acid can produce in 30 seconds at 0° Fahrenheit with the voltage not dropping below the 7.2-volt threshold.

In addition to CCA, some batteries are rated in marine cranking amps (MCA). This is a measure of a battery’s starting power at 32 Fahrenheit.

Most batteries with a CCA rating of 700 or more can comfortably start almost any small to a mid-sized outboard motor.

Another factor to think about is if you’d be starting your engine during the summer or the colder season.

Starting your boat during the winter will require more power. So, the higher the CCA rating, the greater the starting power of the battery.

Make sure to keep in mind the CCA rating of the battery model you’re thinking of purchasing.


  • Reserve Capacity

A battery Reserve Capacity or also known as RC, is to measure the amount of time required for a fully charged marine battery when dropping below 10.5-volts while discharging 25 amps.

If you want your marine battery to perform longer, you’ll need a higher Reserve Capacity battery.

For boats that have many electronic equipment, it’s essential to have a high Reserve Capacity battery to supply enough electricity for all the electronics.


  • Date of Manufacture

Over time, batteries gradually begin to lose their effectiveness and stop being able to maintain a charge as effectively as they once could.

Even if the batteries are new and unused, a battery that’s one year old won’t perform as well as one that was just delivered from the factory.

Always check the manufacturing date to ensure the best possible performance from your battery.

Batteries that are less than 6-month-old has the best performance and can offer excellent starting power or reserve capacity.


  • Maintenance and Design

The older lead-acid type of batteries requires regular maintenance like filling up the acid water.

However, the newer AGM (Absorbent Glass Mat) type of battery is maintenance-free, making them much easier to own and use.

Also, AGM batteries are built tough and leak proof and can withstand constant vibration. More info about AGM battery, here.

Some high-end batteries are even designed with a watertight seal that allows the cells to continue operating even if splashed with water.


  • Amp Hour Rating

Amp hour rating is only applicable for trolling batteries. It is an exact measure of how much amperes a battery can provide for 20 hours. Usually, a higher amp hour rating is the way to go.


  • Vibration Resistance

Turbulence and storms cannot be wholly avoided when riding a boat. Impacts such as these can easily compromise the performance of your batteries.

Having a battery that is durable and vibration-resistant can help it perform better because it can absorb the shocks. Thus, battery life can also be lengthened.


  • Price and Warranty

Of course, you should also look at the price of the battery you want. Batteries come in different price points. Make sure to get one that fits your needs as well as comes within budget.

Looking into warranty details can also prove beneficial in the long run. Some warranties provide generous services to customers while others do not.


Additional Features to Consider

Aside from the factors mentioned above, it is also good to familiarize yourself with a few additional features your battery might have.

Here are some of those features:

  • Intended Use for Marine Battery

Know what purpose you’re getting the boat battery for. Is it for cranking your engine? Or is it for keeping the boat running throughout the duration of your ride?

Some batteries are designed for only cranking or starting your engine. That means these types won’t work at their best for longer periods.

Other batteries like the deep cycle ones or the dual purpose ones can work both for cranking and powering up your boat for longer.


  • Size of Marine Battery

Like car and truck batteries, marine batteries also come in different sizes.

For example, the most common size is the 24M, 31M, and 65 among others.

Before replacing your old battery, determine its size first.

An ill-fitting battery will not work as great as one that fits perfectly.


  • Environment of Use

The sea is a very treacherous and unpredictable place. But you can still observe the environment you’ll regularly be using your boat in.

Rougher and more turbulent waters may need a more powerful battery than a calm and tranquil lake.

Of course, you should also bear in mind the possibilities of water get splashed onto the batteries.

So getting a waterproof battery is a must!


  • Care & Maintenance of Marine Battery

Proper care and maintenance of your battery can mean the difference between it having a longer or shorter lifespan.

You can determine the maintenance instructions of your chosen battery before buying it so choose wisely.

Just remember that all batteries require regular maintenance like cleaning terminal heads, even those deemed ‘maintenance-free.’


Starting, Dual Purpose or Deep Cycle: Which Battery is Best?


There are three main types of marine batteries available on the market, each of which is built for a specific purpose:

  • Deep Cycle Marine Battery

So, what is a deep cycle battery?

A deep cycle marine battery provides continuous 12v power to your boat for a more extended period of time. It has thicker but fewer plates.

This type of battery can be completely drained and recharged a lot of times. A deep cycle battery is much less likely to overheat too.

Just like starting batteries can’t deep cycle, deep cycle batteries are not designed to start an engine. This means you’ll also need a starting battery to crank your boat’s motors.


  • Marine Starting Battery

A marine starting battery can also be called a marine cranking battery. It allows your boat to start, which means it sends power to your boat’s engine when the ignition is turned on.

A starting or cranking battery provides short and strong bursts of power. It has thin plates so that it can give stable and reliable performance.

Since starting batteries are designed solely to start an engine, you’ll need a separate deep cycle battery.

The deep cycle battery is needed to power up any 12v appliances and trolling motors once the starting battery is turned off.


  • Dual Purpose Battery

Dual purpose batteries are designed to offer the best of both worlds.

A dual-purpose battery is designed to provide a large amount of starting power and also to power trolling motors and other electrical appliances.

While the dual-purpose batteries offer excellent performance as both starting batteries and deep cycle batteries, but it has its downside.

Dual purpose batteries will not perform as well as a dedicated, single-purpose battery at either task.


  • Trolling Battery

A trolling motor battery is used to power up your trolling motor. A trolling motor is an electric motor that is used to move a boat through the water.

The best trolling motor battery is usually chosen between 2 types of deep cycle 12-volt batteries, either a Lead Acid Wet-Cell or an AGM battery.

A trolling motor battery can discharge small amounts of current for an extended period of time.

Want to learn more about trolling batteries? Check out this video:


Top Recommended Marine Battery Brands

The best battery brand for you is still a preference only you can determine.

But here are some of the top recommended marine battery brands in the market:

  • Optima

Optima batteries are recognized as one of the long-lasting marine batteries in the market.

This brand uses a proprietary technology – Spiralcell and Pureflow to allow Optima battery to have superior resistance against shock and vibration and enjoy a longer lifespan.

Also, due to the AGM design, Optima battery does not leak or release any fumes even when tipped.


  • Exide Technologies

Exide Technologies is one of the well-known manufacturers of lead-acid batteries.

This brand headquarter is in Georgia and has recycling facilities throughout the US and other parts of the world, including Australia and Europe.

Like many famous battery brands, Exide Technologies provides you with high-performance and stable batteries performance.

Also, the batteries are maintenance-free.


  • Vmax

Vmax is well-known for manufacturing deep cycle capabilities batteries that are high-performance and suitable for heavy-duty needs with exceptional power.

Vmax uses the AGM technology for their battery and it’s maintenance-free without the needs to add any battery water.

You can confidently count on Vmax battery to provide adequate power for all the lights, the trolling motor, the refrigerator, the water pump and more for your boat.

Also, Vmax marine batteries are dual-purpose which is excellent for cracking and trolling use.


  • Odyssey

You would probably hear of Odyssey as this is one of the oldest battery brands in the market.

Odyssey marine battery is well-known around the globe and Odyssey has service stations in over 10 countries.

The Odyssey batteries are well known for its recharge efficiency.

For example, the famous Odyssey 34M-PC1500ST can store up energy without a recharge for 2 years!

Also, their warranty is very attractive; you get a 3 or 4-year full replacement warranty, just as long as you meet the terms.

There are also other best marine battery brands like the ACDelco, Lifeline, Superior Superflex and Trojan you can check them out too.


Marine Battery Structure


To understand a little bit more about marine batteries, it’s good to know how a marine battery is structured.

This will help you understand better how the battery works, and why there are many things you need to consider when it comes to buying one.

There are five major parts in a battery:

  • Container: It is made from polypropylene and is divided into six cells.
  • Positive plate: It is made from lead and other metals to help conduct charge.
  • Negative plate: It is made from lead and other metals to help conduct charge.
  • Plate separators: They are used to prevent short-circuiting from happening and are made from thin materials that make for great insulators.
  • Electrolyte: It is a solution made from sulfuric acid and water and is the reason for the chemical reaction that makes electrons.

Together, all five help convert chemical energy into electrical energy to keep your boat running.

Here is a video showing you how a battery work:


Types of Marine Battery

There are many types of marine batteries that you can choose from. Each of them will have a unique set of pros and cons.

Of course, performance and durability can also be affected with who the battery’s manufacture is.

Below are a few types of marine battery you may want to know:

  • Flooded Batteries

Flooded batteries are also called wet cells. To make electrolytes, they use liquid sulfuric acid to create a path between the positive and negative plates.

The electrolytes created then produce both hydrogen and oxygen while charging the battery.

Flooded batteries require constant maintenance and the refilling of distilled water.


  • Lithium Technology

Lithium Technology batteries use lithium-ion and are one of the most lightweight varieties of battery there is today.

It can discharge about 800 times at 100% and even recharge in an hour. Lithium-ion batteries work the best with electric boats.

The biggest downside of a lithium battery is the cost. It’s an expensive battery.


  • Gel Batteries

Gel batteries use a mix of sulfuric acid, fumed silica, phosphoric acid, and pure water to create an electrolyte.

The gel-like substance has a very sticky consistency which prevents leaks from happening.

This type of battery lasts longer than its AGM counterpart because it has an improved heat transfer which makes it great for performing in high temperatures.


What Is an AGM Battery?


An AGM battery is the abbreviation for Absorbed Glass Mat. They are also called starved electrolyte.

AGM (Absorbed Glass Mat) sealed battery technology was … developed and introduced in 1985 for military aircraft where power, weight, safety, and reliability were paramount considerations. – Northern Arizona Wind & Sun

The defining characteristic of an AGM battery is the very thin fiberglass mat situated between the positive and negative places.

AGM batteries are made to withstand vibration which is good for the boat as it’s constantly rocking on the water.

Watch this video to learn more about AGM battery technology:


How Do You Calculate Amp Hours for a Battery?

Firstly, determine how much amp hour you need. Just add all your 12V accessories and multiply that by 20.

When you have that approximation, look for a battery that can provide you with an amp hour capacity that’s 20% more than what you need.

Want to learn more about Amp Hours? Check out this video:


FAQs About Marine Batteries

  • Q: What type of battery do I need for my boat or vessel?

Most marines vehicle needs two types of battery. First is the starting or cranking battery to kick start the boat. The other one is the deep cycle battery to power up electrical devices and appliances onboard.

The starter batteries serve the purpose of cracking and getting the engine running with a burst of Cold Cranking Amps (CCA). Once power up, the battery is quickly recharged back by the alternator. Also, never deep charge a starter battery as it could cause damage.

Deep cycle batteries are excellent to deliver power over a longer period of time and can be discharged far more. They are recharged by shore power, solar power or using a generator.


  • Q: Can a deep cycle battery start an engine?

While it’s not recommended but in theory, it could. However, to use a deep cycle battery to start a boat is highly depending on the engine ignition requirements.

Deep cycle batteries deliver less cold cranking amps, but might still be sufficient to start an engine with their current but doing so would be wasting the battery as it’s not engineered to handle such task.

If your boat layout only has space to fit one battery, then you should get a hybrid or dual purpose model.


  • Q: Do I need more than one battery?

If you have a few devices and appliances onboard, you definitely need at least a starter battery and one deep cycle battery. If you have limited space and unable to install multiple batteries, then look for a dual purpose marine battery can serve you for both starting the engine and powering up devices.


  • Q: How do I store marine batteries?

Always follow the manufacturer’s instructions when come to store a battery. But here are a few quick tips:

Firstly, never expose battery to water.

Secondly, flooded batteries should be stored and operated upright. AGM and lithium batteries can also be installed at an angle or vertically (but not upside down).

Finally, vibration will degrade battery performance and shorten the lifespan. Make sure to install the battery properly and minimize exposure to vibration as much as possible.


  • Q: Is there any battery maintenance required?

Generally speaking, the type of battery required the most maintenance is the flooded batteries. This kind of battery needs to constantly check for battery water and keep them well ventilated.

As for the maintenance-free type of battery, they require less monitoring. Just regularly check for corrosion is all it needs. And, batteries rarely corrode unless exposed to high moisture.

For deep cycle and dual purpose marine batteries, keeping them charged will prolong their service life.


Marine Battery Charger

A marine battery charger is an essential accessory to have in your boat, as it helps recharge your marine battery whenever needed.

Marine deep-cycle batteries last the longest and charge the fastest if they are charged in distinct phases, which we refer to as the “Ideal Charge Curve,” the charging schedule recommended by virtually all makers of marine batteries. – West Marine

These phases are as follows:

  • Bulk phase.
  • Acceptance phase.
  • Float phase.
  • Equalization.

If you want to keep your battery working for longer, you should aim for shallow discharges. You should also never mix old batteries with new ones.

Want to find the best marine battery charger for you?

Check out these products below or head over to the Best Car Battery Charger and Car Battery Tester post for buying guide and more product reviews:

  • ProMariner 43021 ProSport
ProMariner Gen 3 ProSport 20 Amp 12/24/36 Volt 3 Bank Waterproof Marine Battery Charger 43021
  • The 12/24/36V, 20 Amp, 3 battery bank...
  • Distributed on Demand Technology utilizes...
  • Advanced technology eliminates time consuming...
  • During short or long-term storage, ProSport...


  • NOCO Genius GENM2
NOCO GENIUS GENM2, 2-Bank, 8-Amp (4-Amp Per Bank) Fully-Automatic Smart Marine Charger, 12V Onboard...
  • An 8 amp (4 amp per bank) on-board battery...
  • Safely charge all types of lead-Acid...
  • Advanced safety protection featuring...
  • Rugged and waterproof construction capable of...


  • BMK Smart Charger
BMK 12V 5A Smart Battery Charger Portable Battery Maintainer with Detachable Alligator Rings Clips...


  • Battery Tender 800
Battery Tender 800 is a SuperSmart Battery Charger that will Constantly Monitor, Charge, and...
  • All the charging characteristics of the...
  • The interior is completely encapsulated,...
  • This charger is no larger than a standard...
  • Includes alligator clips and ring terminals,...


  • Min Kota Precision
Minn Kota Precision Digital Chrgr MK 440 PC 4 bank x 10 amps
  • Waterproof, shock and vibration resistant...
  • Saltwater test, fully corrosion-resistant...
  • Short circuit, reverse polarity, arc and...
  • FCC Compliant and UL listed to marine...


Safety and Security

They may not look deadly, but batteries contain highly toxic and dangerous chemicals that may cause harmful effects on you and the environment.

That’s why it’s important to make sure that the battery you’re buying is safe to use as possible.

Make sure that all components are working correctly, and that there are no leaks. If a part of the battery is broken, contact the manufacturer at once and have it replaced.

  • Updated June 20, 2019
James Evans

As a passionate outdoorsman and an automobile enthusiast, James spent most of his time in his garage tinkering with cars and bikes. During his free time, he loves to hike and blog about the things that he has done to keep his ride in tip-top condition.

Click Here to Leave a Comment Below 2 comments
Adme smith - July 5, 2020

I have never read a more simplistic informative piece of commentary before in my life. You guys deserve a shout-out for this article BEST MARINE BATTERY. I have been buying batteries for bass boats over 45yrs. All of the “guru’s” i have dealt with will know of this article. Maybe some novice may benefit as I will.


Theautopartsshop - January 20, 2021

Nice information..its really useful.


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