How to Charge a Jet Ski Battery

The way you charge your jet ski battery is very simple and not too different if you were charging a battery in a car.

It’s important to read the directions on your battery charger before using it, but these are some general directions that can help you.

How to Charge a Jet Ski Battery

To charge a jet ski battery, it’s important you connect the positive charger cable first and then the negative cable. When disconnecting the battery from the charger, you must do the negative cable first and then the positive. Doing it in this order cuts down on sparks and protects the sensitive computer components better.

To get a proper charge on your jet ski battery, it’s best you take it out of the jet ski and store it somewhere dry. Charging a battery in the jet ski is not ideal and not safe.

Do not charge your jet ski battery with a battery charger that is over 2 amps, 750ma to 2 amps is the charging amps you want to use.

  1. Make sure the jet ski is in a secure area where water can’t get to the battery charger or the jet ski won’t roll away on the trailer.
  2. Make sure the jet ski is near a power outlet if you’re using a wall charger or make sure you have long enough extension cord. (See What You Need Below for more details)
  3. Remove any access panels so you can get to the battery. The battery location is either in the front, middle, or rear. Yamaha and Kawasaki’s batteries are mostly in the rear under the passenger seat. Sea-Doo is often under the driver’s seat but 2010 to 2015 it would be in the rear or front. 2016 and up Sea-Doo it’s mostly under the driver or in the front.
  4. It’s best you disconnect the negative cable (black) from your battery when charging as to protect the computer on the jet ski.
  5. Connect the positive (red) charger clip to the positive (red) post of the battery.
  6. Connect the negative (black) charger clip to the negative (black) post of the battery.
  7. Plug in your battery charger to the wall and wait for it to power on and give you the okay.

Before you wander off, you’ll want to wait for the battery charger to test the battery to see if it will take a charge or not. Follow the instructions on your charger to see what each light means.

How To Disconnect Battery Charger

  1. When battery is charged disconnect from the wall outlet first.
  2. Remove the negative battery charger cable.
  3. Remove the positive battery charger cable.
  4. Reconnect battery to jet ski, postive first and then negative cable.

What You Need

How Often to Charge a Jet Ski Battery?

How often you charge your jet ski battery will depend on how often you don’t ride your jet ski. For most people, this means charging your jet ski battery once a year during or after getting it out of winter storage.

If you don’t ride your jet ski for over a month, it’s best to charge it the night before you ride or keep a smart battery charger on it.

The number one cause for a jet ski not starting after getting it out of storage is because the battery died. So make sure to charge your battery the night before you want to ride!

What Voltage?

Most, if not all, jet skis use a 12-volt battery. The biggest thing to worry about is the physical size of the battery.

Every battery is given a size, for example, a typical size for a Sea-Doo is a size 30, 20, or 16. Make sure you get the correct size battery for your jet ski when you replace it.

How Long Does It Take To Charge A Jet Ski Battery?

It can take several hours, sometimes overnight, to charge a jet ski battery. How long you should charge a jet ski battery should at least be for 4 hours, but I recommend letting the smart charger charge it until it’s fully charged. 

The most common thing I see happen is that someone forgets to keep their battery charged during the winter and when spring comes around they want to ride. So they hop on their jet ski and find out that the battery is dead. If they kept a smart battery charger or the solar charger on the jet ski during the winter, then they could be riding.



I began working at a jet ski dealership in 2007, initially in the parts and service area. I then transitioned to the technician side before eventually joining the sales team in 2013. I've done it all! While in sales, I created this website in 2014 to assist others with their common questions about watercraft. I now manage this site full-time, where I answer common questions, offer advice, and assist others with their PWC needs.

I've owned several watercraft and continue to buy, sell, and repair them. Currently, keep my Sea-Doo Spark as my main PWC. Additionally, I have developed tools like a used watercraft value calculator, a pricing calculator, an hour calculator, and more to better assist my readers.


  1. Do you need to remove the positive battery connections before starting to charge the jet ski? Or do you only need to remove the negative connections to the battery before charging?

    • You need to at least disconnect the negative cable of the battery when charging, but doing both the positive and negative will be better.

  2. Installed a new battery beginning of the season but left the sound system on my seadoo on for a couple weeks between uses, battery is dead now. Could I jump it with another seadoo’s battery?

  3. Steven,
    Which trickle charger/maintainer do you recommend for a 2014 Sea Doo GTI for winter storage
    in a garage?
    Please let me know the brand, Voltage, amps, . . . details of which specific one I should get.
    THANK YOU!!!

  4. There is a newer version of the smart charger you recommended. The new one is 2 amp, the old one was 1.1 amp. You mentioned not going over 2 amp, so will the “newer” smart charger that is 2 amp still be ok to use? It says it’s smaller and more powerful, but the more powerful part concerns me.

    I’m going to completely disconnect both the negative AND positive before attaching the smart charger, just to be safe. I’m assuming that’s ok? Do I need to remove the battery from the engine, though, or can I simply leave it where it is and attach the smart charger? There is a label on the battery that says to always remove it before charging, but I’d prefer not to. I’m assuming they want you to remove it because of the odor, gasoline, chance of spark causing a fire etc… Honestly, I haven’t been able to figure out how to get it out, which is why I’m wondering if it’s okay to leave it in place and connect the smart charger.

    • 2 amps is fine, It’s the chargers that are 3 or 4 or greater that is the problem. Disconnecting the battery completely is fine. When disconnecting you want to do the negative side first, it’s just a good habit to do. When hooking up the charger or reconnecting the battery want to do the positive side first, it’s another good habit to do. Removing the battery is recommended. Here is a good video showing you how to do this.

  5. I keep my jetski on a Battery Tender 800 auto which is plugged into the wall outlet in my garage. Lately, the battery tender is blinking red. The manual says that means either the ring post adapters are not connected properly or that the battery has dropped below 4V. I’ve cleaned and reinstalled all connections, so I don’t think that’s the case. Battery is 4yro…time for a new one???

    • 4 years out of a jet ski battery is really good, but it sounds like you need a new one. Keep doing what you’re doing, most people only get 1 to 2 years out of jet ski battery.

      • Thanks so much!!! Maybe my dealership swapped it out two years ago and I just didn’t realize it, or don’t remember. Maybe I’m on my 2nd battery. Either way, I appreciate the free advice!!! Great page, very helpful.

  6. Hi, I took the battery out & charged over night, the jet ski turns on & says reading key, with a light clicking sound continuously, should I jump start the battery with a smart charger for initial start up?

  7. Question. I had a new battery installed last year at the beginning of summer. I forgot to put it on charge over the winter. Can I charge it now and save it? Or is it ruined?

  8. Great stuff here. How often should you charge the battery? It’s my understanding that jet skis do not have an alternator and therefore do not charge the battery when you ride. Should you charge every time you take it out? Once a week? Once a month? Only in the off-season?

    Would love to hear your thoughts.

    • Jet skis don’t have alternators but do have stators. A stator will charge a battery somewhat but it’s designed to maintain enough charge to keep the systems running. You’ll want to put your battery on charge if you’re not going to ride it for a few months like in the off-season. What I do is keep a 5-watt solar panel charger on my battery when I’m not using it and keep the panel where the sun can get to it. It’s not that the solar panel is charging the battery but instead keeping the battery from going stale and dying due to lack of use.


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