The best jet ski battery charger will be a 12-volt smart charger that charges at a max of 2 amps.
You must not charge over 2 amps, and you need to use a smart battery charger. There are also other little details you need to do that we’ll discuss below.
A battery charger sometimes goes by the names trickle charger and battery maintainer too.
Important: Just like a boat, it’s good practice to vent your PWC for a few minutes before working on it or starting it, especially if it’s been sitting, or you just put gas in it.
1. NOCO GENIUS2, 2-Amp Fully-Automatic Smart Charger
My top pick for the best jet ski battery charger is the NOCO GENIUS2 2-Amp Fully-Automatic Smart Charger. Here are the reasons why it’s my top pick.
- 2 Amps – not too much and not too little of charging power, it’s just right.
- Smart charger – It turns on and off as the battery needs it.
- Has a built-in maintainer.
- Can detect sulfation and help restore a battery.
- One of the few smart battery chargers that will try to bring back a dead battery.
- Small – It doesn’t take up much room.
- Its alligator clips are easy to use on batteries.
- Temperature compensation – Needed for hot days or cold days in storage.
Tip: These battery chargers are the same you find for car batteries. So yes, you can use a battery charger made for car batteries for your jet ski battery, so long as it’s 12-volt and meets the correct amps.
2. Battery Tender Plus 12V Battery Charger and Maintainer
My second place pick is the Battery Tender Plus 12V Battery Charger and Maintainer. Here is why I picked it.
- 1.25 amps – Just enough amps to charge a small battery at a good speed.
- Super simple to use – Plug it in, connect to the battery and select 12 volts and let it go.
- Maintainer – Turns on and off as the battery needs it.
- Small – Stores away nicely when not in use.
3. Solar Battery Charger
Consider getting a solar battery charger like this one here*.
A solar battery charger is the best option if you need to charge or maintain your battery without a power outlet.
This is what I use on my setup to help maintain the battery, and I go over the full details here.
How To Charge A Jet Ski Battery
- For best results, remove the battery.
- Connect the positive cable of the charger to the positive post of the battery.
- Connect the negative cable of the charger to the negative post of the battery.
- Plug the battery charger power cord into the correct wall outlet.
- Wait for the smart charger lights to go on and let you know it’s charging.
When charging is done, remove the negative cable of the charger first and the positive cable next.
Battery Charger Is Not Charging Battery?
If the battery charger status lights don’t come on when you connect it to the battery, then make sure you have it hooked up right.
- The positive cable of the charger goes to the positive of the battery, and the negative of the charger goes to the negative of the battery.
- If the lights do come on, but the charger says the battery is bad, you need to get a new battery. The battery is too sulfated to recover.
If the battery charger says the battery is charged, but when you start the jet ski, it doesn’t start, then you only had a surface charge. There could be other reasons why your jet ski is not starting as talked about here.
A surface charge is not a full charge, and you’ll need to get a new battery, no matter what the charger says about the battery charged status.
Only a load tester can determine if the battery is good to start the engine, and not the LED light on the charger. If you don’t have a load tester, many auto part stores will load test a battery for you, and a lot do it for free.
How Do I Know My Battery Is Bad?
- 0 to 11.9 volts is considered bad.
- 12.4 volts is considered weak.
- 12.7 to 13.2 volts is considered good.
What matters more than voltage is amps, and a load tester can only test this. Many auto parts stores will load test a battery for you.
The easiest way to tell if your battery is bad is by listening to the engine area when you try to start.
- A weak battery will struggle to turn over, especially in the water.
- A super-weak battery will give you multiple clicking noises when you press the start button, as talked about here.
- A completely dead battery may power on the gauges, but nothing happens after that.
Most Starting Issues
The majority of starting issues you’ll run into with your jet ski will most often be a bad battery.
So if your jet ski won’t start, replacing the battery is often the first thing you should do, even if you think the battery is fine.
Can You Recharge A Jet Ski Battery and How Often?
Jet ski batteries are rechargeable, but they will die and won’t recharge if you don’t use your machine for 4+ months.
It’s best to recharge your battery every 3 months that you don’t ride.
So if you don’t ride you in August and September, you should charge your battery at least once in October.
Tip: If you’re not riding for a few months, you should take the battery out and use the smart chargers with a maintainer built-in to keep the battery good when in storage.
Avoid Battery Switches
No, your watercraft does not have a battery switch and does not need one either.
Batteries Die From Inactivity
The reason why your jet ski battery dies is not that the thing is always pulling a little power, but instead, it’s because the lead-acid battery go flat if it’s not being used regularly.
If you ride all the time, the battery stays active and lasts for a long time because it’s being used. However, when you leave it to sit for too long, it goes flat, and adding a battery switch doesn’t fix this.
Get A Solar Charger
Instead of a battery switch, consider getting a solar charger. When you’re not riding, hook up the solar charger, and it will keep the battery active and lasting for longer. See how I have my solar charger set up on my jet ski.
What Amps To Charge At?
You want to charge your jet ski battery at a max of 2 amps. Lower amps like 0.75 to 2 amps are fine too.
Going over 2 amps charges the battery too fast for these small batteries, and you can end up cooking the battery, which is very bad.
Charge In Ventilated Areas
When charging your battery, you need to have it ventilated, as lead-acid batteries release a small amount of hydrogen and oxygen when charging.
Leave the access panel, seat, or hood ajar when charging or better yet, take it out. Also, keep the rain off your machine when you have an access panel, seat, or hood open, so you don’t flood it with rainwater.
12 Hours To Fully Charge
It takes about 12 hours to charge an empty battery fully.
It can take longer or shorter depending on what the smart charger considers is best for your battery. This is why we suggest using smart chargers as they turn on and off as they’re needed.
You need to let your battery charge fully and slowly if you want the battery to last. It’s best to not rush these things.
When Should You Replace Your Battery
The most I’ve gone without replacing a jet ski battery is 5 years, but that is because I kept it on the solar charger when I was not using it.
Ideally, it would be best if you replaced your battery every 3 years.
Every Year Is A Problem
If you’re replacing your battery every year, then it means you’re not riding it enough or charging it enough during the off-season.
Lead-acid batteries go bad when they’re not used for months.
You can sometimes recover a dead battery that’s been sitting for a long time by charging it, but a good bit of them don’t recover.
Why Does My Jet Ski Battery Keep Dying?
Avoid Jump Starting
No, do NOT jump-start a battery, especially from your car or truck. I explain why this is bad in this post.
You need a 12-volt battery that ranges in sizes from 16, 20, to 30.
What type of battery you need and what is the best one to get can be found in this guide here.
Adding Water To Battery?
Adding water to batteries is not very common these days.
Most manufacturers are moving to sealed batteries, which makes adding water a thing of the past.
Even if you have a non-sealed battery, I would not add water to it and instead, get a new battery. The trouble you would have to go through to get the distilled water, get a hydrometer, and mess with dangerous sulphuric acid is not worth it if you ask me.
Riding Does Not Charge The Battery
No, riding your jetski will not fully charge your battery. It may give it a surface charge but nothing lasting.
These things use a stator and not an alternator like your car.
A stator only maintains a charge and does not fully charge as an alternator would.