Is It Safe To Jump Start A Jet Ski With Your Truck?

If you own a jet ski, I suggest you avoid jump starts for the following reasons:

1. You can damage your battery.
2. Damaging your truck’s battery.
3. Potentially harming your jet ski’s electronics.
4. Potentially harming your truck’s electronics.
5. Personal safety risks.
6. Lead-acid batteries can explode!

Instead of trying to jump the battery, It’s safer to charge it instead.

The main issue when jumping the battery 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 most jet skis 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 your 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 truck engine is now trying to charge the smaller jet ski battery and smaller electrical system.
2. If the PWC gets started, the rider now needs to remove the connection and with such a vast difference in charge it can create a voltage spike from the alternator which will fry electronics.
3. The dead battery can explode.

Your truck’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 to jump start any jet ski with an obviously smaller battery with big trucks.

Voltage Spike!

The biggest problem is the voltage spike from the alternator.

When disconnecting a weak battery, the running alternator has a sudden load loss, causing a voltage spike seeking a path, possibly harming jet ski components 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 trucks, as many manufacturers warn against boosting the battery.

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 any jet ski.

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 try jump-starting some PWCs from a truck that’s turned off?

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

We still face the voltage spike problem, but now it will start to come from mostly the 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 kickstart the 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.

Jump-starting In Emergencies?

Instead of doing jump starts, It’s best if you can, and highly suggest if you can, to replace the battery in your jet ski.

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

If you find yourself jumping 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 booster 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 truck but switched to super capacitor ones. They seem like magic as they don’t require constant charging, sit uncharged for years, and even charge themselves from your dead battery or another truck’s 12-volt outlet. It’s kind of a life safer if you own something like a jet ski or boats!

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.

A jet ski doesn’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 for the ski don’t last that long due to the abuse the ski takes. 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 start power. Often, it makes someone think their PWC 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.

You should avoid the cheapest jet ski 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 Ski Without A Battery?

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 Sea-Doo 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 Up

Despite what many believe, jump-starting a jet ski is definitely not recommended!

Doing so can damage the battery or electronics of your jet ski, and in the worst case, it could even lead to an explosion.

A jet ski does better if you let the battery charge up by a charger, not jump-starting it. It’s best to stick to a 2 amp battery charger or less, and give the battery plenty of time to get to 100%.