Can you Put A Car Battery in A Jet Ski?

Have you recently bought a jet ski(PWC) and were shocked by the price of replacement batteries? They aren’t too much more expensive than car batteries, however, it seems more logical for a car battery to be more expensive since it’s bigger and more powerful. But you’ve seen firsthand that this is not the case.

Can you put a car battery in a jet ski?

A car battery cannot be used in a jet ski for three reasons, usually they are too large to fit within the jet ski hull, they provide too much amperage and can do permanent damage to your electronics, and they are not designed to be charged with a stator as the case with a PWC battery.

Now you’re looking at the spare battery you bought for your car in case of emergencies and are wondering if it can be used in a jet ski to save a little money. Car batteries could fit in your jet ski, and may even be from the same brand, so it may seem like a promising option.

So, can you put a car battery in a jet ski? Let’s find out.

What Kind of Batteries Does A Jet Ski Use?

If you’re new to using jet skis, you may be unaware of the type of battery they use. This is crucial because it’ll help you realize if you can or cannot use a car battery in your jet ski.

Jet skis use lead-acid batteries typically 16 or 20 amp-hours in size. These batteries are charged differently when operating than a car battery. They use a stator system instead of an alternator to charge them so that trickle charging can be implemented. Trickle charging is simply the slow rate of charge at which the batteries are topped off continuously.

These batteries can go bad if they’re stored a long time since they need continuous charging. A good example would be long storage periods such as winter. The batteries are designed to be discharged completely and charged quite frequently and provide steady electricity to the jet ski.

What Kind of Batteries Do Cars Use?

Cars also use lead-acid batteries. But before you get excited and think you’ve found the answer to your inquiry, there is some information you must know.

The type of lead-acid batteries cars use are engine starter batteries which are usually about 80 amp hours, while PWC’S use small batteries about 20 amp hours.

Engine starter batteries are made to provide a large amount of current in a short period of time. When the engine of an automobile starts, the battery no longer serves as the power source, instead, the alternator does. As the alternator is running, the car battery is being charged, so these batteries do not discharge completely.

The Verdict

You absolutely cannot use a car battery in your jet ski. The car battery is not designed to go through the discharge and recharge cycles that your jet ski must endure. Car batteries also provide way too much power too quickly for the PWC and may cause damage to the electrical system. Which may or may not be able to be repaired.

Jet ski batteries are best charged using Smart chargers that implement trickle charging. Car batteries are best charged by a Smart charger that is putting a higher amperage than a trickle charger. When in use, they must be charged by the alternator of an automobile, which, again, jet skis do not have. They run using a stator system.

You should also note that no battery is meant to be submerged. Although both car batteries and jet ski batteries can get wet, they shouldn’t be dunked in water. Especially when charging! So beware that you should still keep your PWC battery as dry as possible at all times.


When looking for a new battery for your jet ski, it’s best to stick with one specifically designed for it. Venturing into the automobile world may severely damage your jet ski beyond repair and shorten its lifespan. Stick with the battery that’s intended for your PWC to get the most usage from it and to avoid costly repairs.