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How Long Do Boat Batteries Last?

Boat battery being charge using a cable.

I’ve owned several boats over the years, and one of the essential pieces of equipment on any watercraft is the battery. A good battery is critical whether you’re using your boat for fishing, water sports, or cruising around. So how long do boat batteries last? Here’s everything you need to know about boat batteries and how long they last.

What is a Boat Battery?

Let’s start with the basics. A boat battery is simply a rechargeable battery typically used to power things like the engine, lights, bilge pump, and other electrical components on a boat. There are many batteries types available, but they all fall into one of three categories:

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Flooded Lead-Acid Batteries

Bluea lead acid battery connected with a cable.

These are the most common boat batteries and include wet-cell and sealed lead-acid batteries. We typically find these on boats with up to a 30-horsepower motor. These last 5-8 years with proper maintenance.

Absorbed Glass Mat Batteries

This type of battery is typically used on boats with larger engines, usually 30 horsepower or more. They have a longer lifespan than flooded lead-acid batteries and can last up to 7 years with proper care.

Gel Cell Batteries

These batteries are a newer type of boat battery. They have all the benefits of the other two types—such as long lifespan and resistance to damage from vibration—but they don’t produce any gasses or fluids, making them easier to maintain. Most gel cell batteries can last 8-10 years with proper care.

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Lithium Batteries

Lithium batteries are another type of boat battery, gaining popularity, especially in smaller boats. They have a great lifespan and are very durable, but they can be expensive compared to other types of batteries.

No matter which type of battery you choose, it’s essential to keep up with the maintenance to ensure that your boat battery lasts as long as possible. Check the water levels regularly and clean the battery connections frequently. In addition, you should always keep a spare battery on hand in case of an emergency.

Do Boat Batteries Come in Different Sizes?

Modern battery for a yacht with electric motors.

There are three primary battery sizes used in boats:

Group 24 batteries are the most common size and are typically used in small to medium-sized vessels.

Group 27 batteries are slightly larger and have a higher capacity than Group 24 batteries. They’re often used in larger boats or boats with more electrical components.

Group 31 batteries are the largest battery size and are best suited for boats with large engines.

How Do You Know What Size Boat Battery You Need?

First, understand all batteries aren’t compatible with every boat. Group 24 and 27 batteries are the best choices for most boats with a 25-horsepower engine or less. If you have a larger boat or engine, you’ll need to use a Group 27 battery or larger.

In addition, make sure that the battery you select can handle the electrical load of your boat. They rate all batteries by amp-hours (AH), which measures how much current a battery can provide over a set period. A higher AH rating means that the battery can provide more power for a longer time.

You should also consider the cold-cranking amps (CCA) of the battery. This measures how much power the battery can provide at a temperature of 0 degrees Fahrenheit. A higher CCA means that the battery will be better able to start your engine in cold weather.

Boat Batteries for Different Uses

Nanoscale gel deep cycle battery for boat.

People use boats for different reasons. So, it makes sense that various boat batteries match those needs. The variations go as far as powering specific areas of your boat, such as navigation and entertainment devices. Here are some of the most common types and their best uses:

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Deep Cycle Batteries

These batteries can often recharge without as much damage and work for longer times. Deep cycle batteries commonly include trolling motors, lights, radio, and fish finders.

Starting Batteries

We typically use these to start the boat engine, but we can also use them on other electrical components. However, you want to avoid using these batteries for extended periods because they can’t recharge as quickly or efficiently.

Dual-Purpose Batteries

These are a combination of starting and deep cycle batteries. They’re perfect for boats that use many electrical components, like bow-mount trolling motors and fish finders, because they offer the flexibility to use them for both purposes.

How to Maintain Boat Batteries

Black gel lead acid battery.

One of the most important things to remember about boat batteries requires regular maintenance to stay charged. You can ensure that your battery lasts for years if you do this regularly.

Start by checking the water level in your battery’s cells at least once a month. Then clean any corrosion or dirt off the battery’s posts and make sure they are still tightly connected.

Finally, perform an entire charge cycle on your battery every 2-3 months and make sure that the voltage does not drop below 12.5 volts at any point in the cycle.

Does a Boat Battery Replacement Need to Be The Same Brand?

You don’t need to replace your boat battery with the same brand or type. It should work fine if the battery has the same voltage and amperage as your original battery.

Some people may recommend sticking with one brand, but I’ve found that it’s unnecessary. As long as you maintain your batteries correctly, you can use any brand without worry.

What’s the Best Boat Battery Brand?

Premium branded battery with white background.

There is no one best boat battery brand. Every brand has its pros and cons, and what works for some people may not work for others.

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I’ve used lead-acid and lithium-ion batteries from various brands, and I’ve been happy with them. Some brands I’ve used include West Marine, Mastervolt, and Relion.

What Accessories Are a Necessity for Maintaining Your Boat Battery?

You’ll need a few essential accessories to maintain your boat battery properly.

Battery Charger:

Electrical battery charger stationed in the docks.

You’ll need a quality battery charger to keep your battery charged. I recommend a marine battery charger with an automatic shut-off feature.

Battery Maintainer:

A battery maintainer is a great way to keep your battery topped off between uses. This can extend the life of your battery significantly.

Voltmeter:

A voltmeter is a handy tool to check your battery’s voltage. This can help you troubleshoot any issues with your battery and ensure that it’s always working correctly.

Battery Brush:

A battery brush is essential for cleaning the terminals on your battery. This will prevent corrosion and keep your battery working properly.

Jump Starter:

A jump starter is a must-have if you ever have an issue with your battery. This can help you start your engine if your battery dies, and it can also charge your battery in an emergency.

Battery Box:

A battery box is essential if you don’t want your battery exposed. This can protect your battery from harsh weather and any damage that may occur on the boat.

Battery Hold-Down Tray:

A battery hold-down tray is crucial if you’re worried about your battery falling out. This can keep your battery locked in place and prevent it from moving around while you’re on the boat.

If you follow these tips, you should be able to get a good amount of use out of your boat battery before it needs to be replaced. Remember to keep up with regular maintenance, and you’ll be all set.

Before you know it, you’ll have an entirely powered boat ready to hit the water. So what are you waiting for? Get out there and start enjoying your boat!