Here’s Why You Should NOT Jump Start Your Jet Ski With Your Car

Yes, you COULD use your truck to jump start the dead battery in your jet skis, but it’s not recommended due to the following risks:

  1. Damaging your jet ski’s battery.
  2. Damaging your car’s battery.
  3. Potentially harming your jet ski’s electronics.
  4. Potentially harming your car’s electronics.
  5. Personal safety risks.
  6. The battery can explode!

While it might sound extreme, I’ve seen these problems occur when people attempt to jump the batteries from their trucks. It’s safer to charge your jet ski’s battery instead.

The Biggest Reason Why It’s Bad

Sea-Doo GTI battery location next to fuses

The main issue when jump-starting with a truck is that people often do it while the truck’s engine is running.

When the engine runs, the alternator generates a significant amount of power, often too much for the jet ski to handle.

Connecting your dead jet ski lead acid battery to a charged truck battery causes the truck’s computer to detect a load and increase the alternator’s power output.

If the jet ski’s battery has been inactive for a while, it may be sulfated, making this situation even riskier.

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 is much bigger than a jet ski’s and can’t handle the power from some vehicles, especially large trucks. It’s surprising how many people attempt jump-starting the obviously smaller battery with big trucks.

Voltage Spike!

The biggest problem is the voltage spike from the alternator.

When you disconnect a weak battery, the running alternator has a sudden load loss, causing a voltage spike seeking a path, possibly harming you, jet ski or your truck’s electronics.

Some call it “the alternators working against each other,” but it’s the same issue. It’s important to know your jet ski electronics can’t absorb spikes as well as your truck and may get damaged. This is even a concern with modern cars, as many manufacturers warn against jump-starting.

Exploding Jet Ski Batteries

It’s surprising, but lead-acid batteries can also explode when they become too sulfated.

Batteries sulfate when left unused for months, which is common for jet skis.

A surge of power under the right conditions can cause a battery to explode. All lead-acid batteries have a warning about this potential explosion.

Engine Off…

If the issue arises from the truck engine running, would it be possible to jump start a battery from a truck that’s turned off?

Yes, you can jump start from a car with the engine off, but it’s better to disconnect the car battery entirely.

We still face the voltage spike problem, but now it can come from the jet ski’s stator, as it lacks an alternator. Stators and alternators are similar, but the issue is smaller with a stator because it generates less power. However, the problem still exists.

The best way to jump start a battery is to use another battery not connected to any other equipment. It’s also advisable to use a battery of similar size to what’s in your jet ski.

In Emergencies

Instead of jump-starting, It’s best to replace the battery in your jet ski.

However, in emergencies, you can use a separate jump starter battery pack.

If you find yourself jump-starting your PWC frequently, investigate why your battery keeps dying. Personally, I use a solar charger on my jet ski all the time and replace the battery after 5 years. I even use it on my riding mower’s battery, it’s super effective!

I do understand that jump starter packs require maintenance, which can be a hassle. Fortunately, super capacitor jump starters are a solution to the problem.

Super Capacitors

I used to have a regular battery jump-box in my car but switched to super capacitor ones. They seem like magic as they don’t require constant charging, can sit uncharged for years, and can even charge themselves from your dead battery or another car’s 12-volt outlet. It’s kind of a life safer if you own a jet ski or boat!

Dying Slowly Over time

If your jet ski’s lead-acid battery is simply dying over time, then you need to fix that problem or else you’ll always have a dead battery.

Jet skis don’t have a battery switch, but there isn’t much that will drain the battery unless it’s some aftermarket parts. The truth is that batteries go flat when not used for months. Also, some batteries get old or have a manufacturer defect in them, causing them to die sooner.

I suggest using a solar battery charger that you keep on your jet ski when not using it for long periods of time. A solar charger is not meant to charge a dead battery, but merely keep it happy and alive.

Lastly, it could simply be that your jet ski battery is bad. The batteries in jet skis don’t last that long due to the abuse they take. If the battery is a few years old, I would get a new one.

Corroded Grounds

If you’re having starting issues and the engine in the jet ski is a few years old, you could have some corroded grounds.

This is especially bad around saltwater areas, the grounds start to corrode, and it affects the starting power of your jet ski. Often, it can make someone think their jet ski’s battery is bad when it’s not.

You’ll know the grounds are corroding just by looking at the battery terminals, if they’re corroded, so is any other exposed metal connector in the engine compartment.

$50 To $300

Sometimes, the only solution is to get a new battery.

When it comes to prices on jet ski batteries, you’ll find they range from $50 to $300 per battery. Then to get one installed can cost you even more than that.

Do not buy the cheapest battery you can find. I can’t tell you how many times I’ve had people buy riding mower batteries and rig it to fit in their jet ski’s battery compartment, complaining it’s not starting right. You need the exact battery made for your jet ski, as covered here.

Running Without

I’ve got to make note of this one, as I’ve gotten a few people ask me… but will a jet ski run without a battery? As in, can someone start up the jet ski, take the battery out, and put it in another one so they can get to riding?

The answer is no.

Your jet ski needs a battery always connected to it to dump its charge, without it the computer will kill the engine. This is common with most fuel injected engines. If you have a carbureted jet ski, a 2-stroke in most cases, it’s still the same. Some older ones “could” do it, but it won’t be useful, so overall, DON’T DOT IT!

Sum It Up

This may shock a few people, but it’s best you don’t try jump-starting the battery in your jet ski with a car or truck.

Not only is it dangerous, as the battery can explode, but it can damage the electronics of your jet ski. You can use a jump pack to start your engine in your jet ski, or even another battery not connected to a running engine.

Ideally, you should remove the old bad battery and put in a new good battery if you’re having starting issues. You don’t want to jump a bad battery and get stranded when the engine cuts off for whatever reason, especially since jet skis don’t have alternators to charge the battery.



I started working at a power sports dealership in 2007, I worked in parts, service counter, and as a technician before moving to sales in 2013. I created in 2014 to answer common watercraft questions I would get from people. Now managing the site full-time, I continue to provide advice and web tools for my readers about watercraft. I've owned several watercraft, with a Sea-Doo Spark as my current main PWC.


  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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