Boat Battery Lifespan & How To Extend It [Easy Steps]

A boat battery can last 3 to 5 years, with some even going to 10 years due to their size and with proper maintenance.

If you find your boat battery is dead after one year or the start of a new season, then it’s because you’re not doing proper maintenance on the battery.

Lead-acid batteries, which boats use, go flat and die if they’re not being used. If you’re not driving your boat for more than a month, then you need to do some extra steps to keep your battery going for years.

Extending Your Battery’s Lifespan

When it comes to your boat, and it’s battery, you need to do more than turn the battery switch to off.

The problem is not that there is a small draw of power on the battery, but the fact that your boat sits for too long. Lead-acid batteries will sulfate when not used for months, which is why your battery dies or becomes weak.

To keep your batteries from sulfating you need to keep them active. Keeping a boat battery active can be as simple as riding it at least once a month or keeping the battery charged.

There are two good options when it comes to keeping your boat battery in great shape, a smart battery charger or a low-wattage solar panel charger.

1. Smart Battery Charger

If you have power near where you keep your boat, you can get a smart battery charger.

You want to use a smart battery charger, as it turns on and off as the battery needs it. Some models of smart battery chargers even have a desulfation mode, which can help bring back weak batteries that have been sitting for too long.

You can get a smart battery charger here (ad), this one has dual battery charging capabilities. It’s also ideal to get marine battery chargers, as they’re sealed.

When you’re not going to be using your boat for months, you should keep the battery on charge or at least charge it the night before you plan on riding.

2. Solar Battery Chargers

Another option, and my favorite, is to use a solar battery charger (ad). I like this option because it doesn’t require a wall outlet or power, and is far easier to install and deal with.

The key thing about solar chargers is that you don’t want to exceed 5-watts unless you use a charge controller. Too much wattage and it can overcharge the battery, but a charge controller will stop that.

The goal of using a solar battery charger is not so much to charge the battery, but to keep it active and from sulfating. It’s because of this that the solar panel doesn’t need to be in direct sunlight, just some sun needs to get to it. So the panel can be flat, vertical, crooked or whatever, so long as it’s exposed to the outside and can get some sunlight.

How Often Should You Charge Your Battery?

You should charge your boat battery every 30 days, the night before you go ride at least, to keep it happy.

If you can, what I like to do is keep the solar battery charger hooked up all the time and when I’m done riding for the day I put it over the boat cover and leave. I don’t know when I may ride again, but I do know the battery will be ready the next time I go ride. Since I use a low wattage solar charger on my boat battery it doesn’t drain it and when the sun comes out it keeps it happy. The only negative is that there is a tan line of my solar panel on my boat cover, though hanging the panel on something would fix this.

Reviving Dead Batteries – It’s Possible

Reviving a dead boat battery can be a 50/50 shot.

Bringing back a dead battery really depends on the age of the battery and how long it sat. If it’s under a year old, the chances are good that just putting it on a charger will bring it back.

If the battery is more than 3 years old, it’s often just best to get a new battery. I would try to use a smart battery charger with a desulfator first, as you have nothing to lose.

When the battery is over 5 years old and it’s dead, then just call it and get a new battery. You’ll only be creating new problems by trying to bring back a bad battery.

10 Year Lifespan Is Possible

If you do the proper maintenance and keep the battery charged when it needs it, then it’s possible to get 10 years out of a battery, but it’s a gamble.

Batteries are funny things, you may get 10 years out of one but 2 out of the next one. Sometimes new batteries are bad, and sometimes a battery that seems dead just has corroded terminals.

Boat batteries tend to last longer than jet ski batteries, as they are larger batteries. Larger batteries have larger plates and don’t sulfate as quickly.

You should set your expectations to 3 to 5 years for your boat batteries, but if you get 10 years, then you won and should look into getting a new battery soon.

How Do You Know Your Boat Battery Is Bad?

The only way to know if any lead-acid battery is bad is to load test it.

To load test the battery, you need to use a load tester and NOT a multimeter. The cheapest way to load test a battery is to take it to the local autoparts store and let them do it.

If you don’t want a store to test your battery and want to have the tool yourself, you can get battery load testers here (ad).

You need to measure the amps, not the volts. A bad battery can still read the correct volts, but put a load on it (amps) and it drops off. Generally, if the boat is giving you multiple clicks from the engine, then it’s a weak or bad battery.