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Jet Ski Battery Drain (Causes, Issues, and More)

If you are suddenly noticing that your jet ski battery is dying far faster than usual, then you have a battery drain issue. This can be a real pain in the rear end if you just come across it on your trip to the beach.

So, if you are wondering, why does my jet ski battery keep dying, well let me clear that out for you.

Jet ski batteries go wrong due to sulfation. This happens when inert lead sulfate builds upon the plates of a battery and makes it lose power quickly by damaging the battery. This occurs by making the battery sit idle for too long. Jet skis are used occasionally, and the batteries are smaller, which is why they go bad much faster than car batteries. 

If you are reading this, I know you are also facing the same problem and I know it is annoying to replace the battery every year.

This is why this article is here to answer all your questions about why your jet ski battery drains so fast and what you can do to make it last longer.

Reasons Why Your Battery Keeps Dying

Unlike other conventional vehicle batteries, jet ski batteries are smaller, which means they will go bad faster.

Some practices can make the battery in your jet ski last much longer. But before that, you must know the reasons why it goes bad first. 

Unlike car batteries, jet ski batteries sit idly most of the year due to less use, which causes them to sulfate.

However, car batteries also sulfate if you do not drive them for a long time. Still, jet ski batteries sulfate faster due to their small size.

There are some other reasons why your battery keeps dying. 

Overcharging Your Battery

Overcharging is never a good thing for your battery. In fact, soaking the battery frequently will reduce its capacity, in which case you will see the battery is not charging to its full capacity anymore. Overcharging your battery will make it explode too.  

Although jet ski batteries are small, they take a long time to charge fully. Thus, it makes it harder to know when to unplug the battery from the setting. 

The Cold

Usually, people do not ride their jet skis in winter and store them up in their garages until it’s time for summer again.

But, the battery is exposed to the cold in the garage, and if you don’t store the battery in a warm place, it will die in the winter. 

The cold weather and the lack of charge will kill the battery, and most of the time, it can’t come back to life even after charging it. 

Your Battery Is Defective

Batteries are being produced in mass amounts in factories. We all know that production on a big scale brings around faulty products as well. It might be that the battery that came with the jet ski or the one you replaced is defective. 

Defective batteries won’t give you a full capacity service. It’s due to a leak or a technical problem in the battery when it was produced. 

Non-Battery Related Issue

There might be cases where your battery is not the problem. Instead, it’s some other part of the jet ski. There are many parts to look into.

For example, wrong rectifiers, bad grounds, blown fuse, corroded battery, broken keys, and a bad computer. 

It might be a loose electrical connection, a broken gauge, or you might have accidentally left the key on, not placing the correct battery according to the vehicle.

A complete inspection of the battery and all connected with it will bring out the main problem. 

Tips to Make Jet Ski Battery Last Longer

By now, you already know that leaving the battery of the jet ski idle will make it lose its life very early. And it will absolutely die if it freezes in winter.

The battery needs to be used all the time to maintain its life as long as possible, but no one really rides a jet ski all the time. 

Therefore, here is some advice that you can use to prolong your jet ski battery. 

Winter Storage And Trickle Charge

Firstly, when winter comes, the jet ski goes back to the garage for storage but disconnects the battery and keeps it in a place where there is room temperature.

A frozen battery is as good as dead. And don’t let corrosion take place on the terminals. Before storing it, apply grease to the terminals.

And if there is already some corrosion, use a mixture of water and baking soda. Apply it and after a while, remove the rot with a toothbrush.

Finally, when you keep the battery in store, remember to keep it in charge all the time. This might sound bad for the battery, but that’s why you have to pick a suitable charger. Buy a trickle charger.

It keeps charging the battery with less voltage, basically, trickle charging the battery. You don’t want your battery to overcharge and lose power over time.

Picking The Right Charger

Pick a suitable charger, and buy a smart charger that charges the battery to its full capacity and automatically stops when the battery is charged.

A smart charger will help you save time monitoring the battery and also make it last longer. Use this for regular charging. This type of charger is used regularly to charge your jet ski.

A trickle charger or a solar charger is best for winter storage time. A solar charger also charges at a low voltage, keeping the battery active all the while making sure not to overcharge it. 

Don’t Jump Start Your Jet Ski

It would be best if you didn’t jump-start your jet ski with the help of your car, as this process can overcharge the battery and kill it. Instead, jump-start your jet ski using a freestanding method. 

It’s the safest way to get your jet ski started. The method uses a freestanding battery that is not connected to anything else. Its sole purpose is to provide sufficient power to start the jet ski.

Do not start your jet ski with the help of another jet ski battery. This will harm your jet ski battery down the road.

When Should You Replace The Battery In Your Jet Ski?

A jet ski battery lasts up to 3 to 5 years by keeping it charged when unused and storing it in winter. And if you don’t keep charging it, then that battery is going to last only for a year. 

If your jet ski is lying in the open in winter, then you can assure yourself that you need to change the battery. And if you don’t store the battery correctly, you will need to change it. 

Moreover, you’ll know to change the battery when you hop on your jet ski, put the key in, and all it does is click. One click from a lousy start relay is okay, and that does not indicate a battery issue.


Owning a jet ski can be an amazing way to enjoy the water. But like any vehicle, their batteries wear out over time, and the battery in jet skis comparatively wears out faster than other batteries.

Thus, most of us are left wondering, why does my jet ski battery keep dying? Hopefully, by now you have the answer to that question.

If you take good care of the battery, then it will last you in years to come. Thank you for sticking around till the end!