Can You Jump Start A Jet Ski Battery? [Better Options]

Many of have been there, we want to take our jet ski out on the water but when we go to start the engine we find out the battery is dead.

This problem tends to happen more at the start of the season, when people have not used their jet ski for months.

Since you can jump start a car, and a jet ski uses a 12-volt battery, can you jump start a jet ski with your car or truck? The answer is no, but I need to explain why it’s a bad idea.

Can You Jump Start A Jet Ski With Your Car?

Yes, it’s possible to jump start your jet ski’s battery using your car, but it’s very risky and should NOT be done.

When jump-starting your jet ski battery with your car, you run the risk of damaging:

  • Your jet ski’s battery
  • Your car’s battery
  • Your jet ski’s electronics
  • Your car’s electronics
  • And yourself!

There is also the risk of a battery exploding. Yes, lead-acid batteries can explode, especially ones that have been sitting dead for months.

Why Jump Starting Your Jet Ski From A Running Car Is BAD!

The problem of jump-starting a jet ski battery with a car is that people do it from a car or truck that has its engine running.

When the engine is on, the alternator is producing power, and that is a problem.

You hook up your dead jet ski battery to a charged car battery the computer on the car sees a load, so it kicks up the alternator to make more power. If the jet ski battery has been sitting for months, it’s probably sulfated, which makes this even worse.

There are 3 problems that are now created:

  1. The car engine is now trying to charge the smaller jet ski battery and smaller electrical system.
  2. If you get the jet ski started, you now have to remove the connection and such a vast difference in charge can create a voltage spike from the alternator which will fry electronics.
  3. The dead battery can explode.

Your car’s electrical system and wiring is much larger than a jet ski’s and the jet ski can’t handle the power coming out of some vehicles, especially large trucks.

The worst is the voltage spike from the alternator. When a running alternator suddenly loses a large load, like disconnecting the weak jet ski battery, a voltage spike happens, and it needs somewhere to go. You can get 100-200 volt spikes that are now looking for a place to go, either in you or the electronics of your car or jet ski. Some call this “the alternators working against each other“, but it’s the same thing. The electronics of your jet ski can’t absorb the spikes as well as your car and will get fried. This is even an issue on modern cars, with many manufacturers putting extra warnings on jump-starting.

Lead-acid batteries can also explode when too much sulfation takes place. Batteries sulfate when left alone and not used for months, which is very common for jet ski batteries, and a surge of power and the perfect mix can have the battery explode. There is even a warning sticker on all lead-acid batteries about them exploding.

Can You Jump Start A Jet Ski From A Car That Is Not Running?

If the problem comes from the car engine running, does that mean you can jump start a jet ski from a car that is off?

You can jump start a jet ski from a car with the car engine off, but it would be better to disconnect the car battery completely.

We still have the voltage spike problem, but now it can come from the jet ski’s stator, as it does not have an alternator. A stator and alternator are very similar, and the problem is smaller because a stator doesn’t produce as much, but the problem is still there.

The best way to jump start a jet ski battery is with another battery that is not connected to anything else. It’s also ideal to use a battery of similar size, don’t try jump-starting your jet ski battery with a tractor battery!

Basically, you should only jump start a jet ski from a jump-starter pack.

You Can Use Jump Starter Packs

Jump-starting your jet ski from a car is not the best way to go about this. In fact, the best thing to do is simply replace the battery with a good one.

But we’ve all been in a tight spot before, so it’s okay to jump start your jet ski from another battery that’s not connected to anything. In other words, you can use a jump starter battery pack.

If you’re having to jump start your jet ski a lot, then you need to figure out why your battery keeps dying. I, personally, keep a solar charger on my jet ski all the time and never have any starting issues until the battery is 5 years old, and then I replace it.

I understand jump battery packs kind of suck, they too need to be kept charged, which makes them almost not worth it.

Though, there does exist a solution that fixes the jump starter charging problem, and it’s super capacitor jump starters.

Keep A Super Capacitor Jump Starter In Your Car

I used to keep a regular battery jump box in my car, but quickly replaced them when I found out about the jump boxes that used super capacitors.

They almost feel like magic because you don’t need to keep them charged, can sit uncharged for years, and even charge its self off your dead battery or another car’s 12-volt outlet.

But they work, and will work great for your car and jet skis!

Charge The Dead Jet Ski Battery Instead!

If you’re not going to be riding your jet ski until the next day or several hours from now, just charge it instead!

The stator on your jet ski is not always going to charge your battery, so don’t think riding your jet ski will resolve your problem.

Most of the time the battery needs to be charged, no need to jump start it if you have the time.

It’s good practice to charge your jet ski battery the night before you ride, or keep a smart battery charger on it when you store it for the winter.

Are New Batteries Already Charged?

If you’re in a time crunch and need to get on the water right away, then you can buy a new battery.

Here is a chart to figure out what battery you need for your jet ski.

The sealed jet ski batteries should be charged and ready to go.

Jet ski batteries that have the acid pack that you need to put on are not charged and must charge overnight if you want the most life out of the battery. Yes, it’s enough to start the engine a couple of times, but that battery will not last unless you fully charge it the first time.

The honest truth is that you should not be jump-starting a jet ski, and instead charge the battery properly or buy a new battery. If you’re at the point of needing to jump start the jet ski battery it’s either bad or going bad and all roads lead to you getting a new battery.

2 thoughts on “Can You Jump Start A Jet Ski Battery? [Better Options]”

  1. YAMAHA 2022VX – Battery appears to be draining all the time, thinking of installing a cut off switch as something is pulling current. Anyone else?

    • It’s best to do some tests to see if there is a constant power draw before installing a switch. I would avoid a battery switch altogether and instead go with a solar battery charger:

      Most of the time it’s not a draw on the battery, but that the battery is not being used enough and it goes flat. A solar charger will keep the battery active and happy, and far easier than installing a battery switch.


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