Do jet skis have a charging system? Is it an alternator? Well, some may find this odd, but they don’t use an alternator and use a stator instead.
While a stator is similar, there are many differences between the two that I must cover.
The jet ski Stator explained
The key point, a stator and alternator work very similarly, both will charge the battery, but a stator is more focused on maintaining the charge (“trickle charge the battery“).
Some manufacturers will repurpose motorcycle engines, which means a stator for both a jet ski and motorcycle are similar, and the video below on motorcycle stators is a good one to watch.
For those that wonder, here are the reasons why a stator is used over an alternator.
- Stators are smaller.
- Stators can be built into the engine, which cuts down on weight and costs of manufacturing.
- Stators are simpler.
Compared to cars, a jet ski has a lot less going on, and a jet ski operates in wet and rough environments, all the features above are a must.
Key Differences Between an alternator and a stator
The key difference is the magnets and how it’s set up when comparing stators and an alternator.
When it comes to generating electricity, both play by the same rule book. They both work by moving copper wires through a magnetic field.
But here’s the twist that many people don’t know about: a stator gets its magnetic power from fixed magnets, while an alternator relies on electromagnets from copper coils. That’s where these two really set themselves apart, and it greatly affects how power is generated for a battery.
There isn’t a need to rely on the engine RPMs, an alternator can generate its own magnetic field.
RPM Dependent
A stator is dependent on the RPMs, and why it’s more of a maintainer than a charger. It’s interesting to note, that do to the irregularity of power, a voltage regulator (also called a voltage rectifier), must be used.
Fixed magnets allow stators to be smaller and lighter, and you can put them inside the engine block.
Voltage Rectifier
A voltage rectifier takes the power produced by the stator and converts the AC (alternating current) power into DC (direct current) power and smooths it out to make it more constant and predictable for the battery and accessories.
AC power is easier to regulate the power, and that is what both a stator and alternator generate.
Signs Of A Bad Voltage Regulator
A flashing “12-Volt Low” on the display is a common sign for a jet ski, or any jet ski, that the voltage regulator has gone bad. But this could also mean the battery is bad, grounds are dirty, or a fuse is bad in the jet ski. A bad voltage regulator can be what’s draining your battery, and replacing the battery won’t fix the issue.
From what I see, is that most of the jet ski electrical issues tend to be a bad battery more often than anything else. It’s more common that you’ll put 100 or more hours on a jet ski before the battery is not the main problem.
Replacement
I consider replacing a voltage regulator as not being hard, it’s often next to the battery and comes off with a few screws and unplugging wires. (Most people could replace it with simple tools!)
Just make sure the battery is disconnected before you replace it.
If the jet ski battery keeps dying on you, then I got a post that covers that here.
Testing The Charging System
Testing the charging system and stator of your jet ski to know if the stator or voltage regulator is working fine is similar to any other small engine. With having the vessel out of the water, here are the steps to test if your stator is good or bad.
- Connect a volt meter to the battery.
- You must keep the engine on and look at the voltage reading.
- Rev the engine to 5k RPMs and look at the voltage reading.
- Turn the engine off, don’t run the jet ski out of the water for no more than 30 seconds.
If the voltage reading on both is NOT between 13.5 and 15 volts, then the voltage regulator or stator is bad. If the voltage reading is over 15 volts at 5k RPMs, then the voltage regulator is bad. A jet ski battery is 12 volts, but higher voltages are needed to charge the battery, but too high is a problem too.
If you’re having battery problems, the best solution is to get a new battery.
No Battery, No Go
I’ve had a few people ask me about running without a battery, mostly because they need a jump and only hold one good battery.
You can’t swap your battery out and expect the jet ski to run fine. The engine needs a place to dump its charge, and without it the engine will stop running.
Motorcycle engines?
Motorcycle engines use stators, and I made mention that some jet ski manufacturers repurpose motorcycle engines.
It’s not a bad thing, but when the manufacturer also makes motorcycles, which is a far bigger market, it only makes sense to repurpose the engine. By repurposing, they use stainless-steel bolts and other things to hold up to the corrosion and the wetter environment.
One easy way to tell if your engine is a repurposed motorcycle engine is to see where the oil filter is located. On a motorcycle, it makes sense since it’s on the side. With fiberglass hulls, that would be a horrible location for a jet ski. Though, you’ll see them moving the oil filter to an easier to get to location these days.
It’s not just motorcycles, either, some repurpose snowmobile engines, which is kind of funny as they’re both driven in very different climates. It’s just an interesting tidbit, like how Ski-Doo was supposed to be Ski-Dog but due to a translation error, we got Ski-Doo. Or, at least, that’s what I’ve been told.
Can you Jump Start Your Engine Or Will You Fry The Computer?
While you can jump start your engine, it’s best you don’t.
Not many people realize how dangerous jump-starting any lead-acid battery is, they can explode. Also, jump-starting from your car or truck is not an idea as they output more power than the computer can handle, especially when the battery is completely flat.
You can jump start from a battery pack, like a jump starter kit, or even another lead acid battery not connected to anything. I cover more on this subject here.
Most of the time, people needing to jump start their jet ski is because they left it unused for months, like during the winter. It’s best you remove the battery from the jet ski and charge it the night before you want to ride next season.
Consider A solar Charger
If you’re having battery problems, then it’s mostly because you’re not driving enough.
Lead acid batteries go flat when not used for months.
If you get yourself a solar battery charger, it will help maintain the battery and keep the vessels ready to go on your next ride. They’re so stupid simple and effective, it makes me wonder why the manufacturers are not just baking them into the covers? Yamaha did this for a little bit with their Jet Boat line, but it never really took off. Do this, and you’ll easily get 3 to 5 years of life out of your jet ski battery.
If you’re looking for how to charge your jet ski battery, see the post on that here. You don’t need to charge your jet ski battery often, only when it’s been sitting for months unused. You can overcharge a jet ski battery, so make sure to use a smart charger. You can use a car battery charger, so long as it’s 12 volts and under 2 amps, along with it being a smart charger (turns on and off as it’s needed).
This is off track from the earlier question. I have a 2003 Honda Aquatrax (sp) It’s been serviced winter and summer. Garage kept. Do have cover for it. Practically new tires on trailer. Low hours. Is it worth keeping since we don’t take it out much or should I sell it?
If it’s running fine, I would keep it until it doesn’t. Honda made some great jet skis, but certain parts will be difficult to find, but you can still do the basics like an oil change and such.