Can you add water to a jet ski battery?

Oftentimes, when it comes to maintenance on a Jet Ski, many overlooked features should be done regularly. Most namely, if and when to add water to the Jet Ski battery. Throughout this article, we will cover a variety of topics that will greatly help you.

Can you add water to a jet ski battery?

Jet ski batteries should be periodically checked for proper water levels. If you have a wet battery, you can remove the caps and add water to your jet ski battery to the appropriate levels. This will prolong your battery’s life. If you have a sealed or AGM battery, there is no need to add water.

Why Do You Add Water To A Jet Ski Battery?

Jet ski batteries, much like any conventional battery, contain a mixture of sulfuric acid and water which is also known as a liquid electrolyte. During the lifecycle of the battery, it will consume water, but not sulfuric acid. As water levels start to get low, you will see poor performance from your battery. This usually presents itself in your battery not fully charging or your jet ski not charging correctly.

The first thing to check when you notice your battery not functioning properly is your battery’s water levels. At this point, it may be too late, so always check

When adding water to a jet ski battery, you have to make sure that you do not overfill the cells. When your jet ski battery is charging, the electrolyte solution’s density will increase. If you add too much water before charging the battery, the electrolyte levels can expand, causing your battery to overflow. This can quickly damage a battery or cause a dilution of the electrolyte which results in battery performance deterioration.

Why you should add water to your jet ski battery

Adding water to a jet ski battery is important for its health and to keep it function properly. But there is more to it than just adding water.

Just about every expert recommends using distilled water and this is added into the caps over the individual cells until the levels in each cell are level with the recommended fill line. Others say that you can also buy pre-mixed additives from an auto shop or online.

The mix usually contains a 10-15% acid to pure water ratio. So distilled or pre-mixed acid can be used, but never add tap water due to tap water having chemicals that may damage the battery. 

How To Know When To Add Water to a Jet Ski Battery

Periodically check your jet ski batteries water level. This should be done about every two weeks when you ride and before and after winter storage. You will know you need to add water when water levels are low on the gauge of the battery.

If you are experiencing charging issues on your jet ski, it may be time to add water to your battery, or it may already be too late.

If the lead plates on your battery are exposed, it is already too late. You can try and nurse the battery back to health, but it will never perform perfectly again.

One way to find out if your jet ski battery needs water is by checking the voltage with a battery meter. If you are getting a low reading, check the fluid levels on the cells. The battery on your jet ski should have a water level gauge on it indicating how much fluid is in each cell. If your gauge is reading low, open the caps on your battery and fill the cells with distilled water. 

After your battery has been filled, recharge your battery and check for voltage. If your battery is fully charged, you should be good to go. If your battery still will not hold a charge, it may be time for a new battery as the cells have likely become damaged.

How To Safely Add Water To A Jet Ski Battery

When working around any battery, not just a jet ski battery, you should take special precautions. Batteries store a lot of electricity and harmful chemicals, so having the right personal protection equipment is key. You will want to wear protective eyewear and gloves at all times to prevent personal injury.

Step 1. – Check for any warning labels. You will want to make sure that you can service the battery before adding water. Some batteries will say “DO NOT OPEN” meaning you cannot service the battery. Others may say ‘KEEP VENT CAPS TIGHT FOLLOWING WATERING SERVICE” which means you can service the battery as long as the vent caps are tight. 

Step 2. – Figure out which cells need water. Check each cell’s level gauge to find out where you need to add water and how much you need. 

Step 3. – Use the right fluid. Check your owner’s manual or the battery’s manufacturer’s guide to find out if you need to use distilled water or a pre-mixed solution from your local auto or marine shop.

Step 4. – Add water to the battery. Follow the manufacturer’s recommended procedure for adding water to the battery. 

How Often Do You Need To Check & Add Water on a Jet Ski Battery

The frequency in which you add water to your jet ski battery is going to rely solely on how much you use your jet ski. Your battery is going to consume the most water when it goes through cycles, so if you are using your jet ski often, you will need to frequently check your battery’s water levels.

After a few times that you have checked, you should figure out how often you will need to add water to your battery. Since batteries consume more water in the warmer weather and jet skis are mainly used in the summer, it is always a good idea to check your water levels once a month.

Always check your battery levels when you store your jet ski as well as when you bring your jet ski out of storage for riding.

Replacement Jet Ski Batteries

If you do need to replace your jet ski battery, our favorite brand is Yuasa.

Yuasa is currently the most popular jet ski/power sport battery brand. The most common Yuasa batteries for new jet ski models are:

If you go on Yuasa’s website, you can look up the specific battery recommended for your jet ski based on make, model, and year.

Common Battery Questions

What Voltage Are Jet Ski Batteries?

Jet Ski’s use a 12-Volt battery and be sure to not charge these batteries beyond 2 amps. This means that whenever you get a new battery it will require several hours to charge

Can You Use A Lawnmower Battery In A Jet Ski?

Technically these batteries can work, but the plastic walls of lawnmower batteries tend to be extremely thin in comparison to PWC batteries. The constant abuse that a Jet Ski takes on the water could break the battery filling and could leak battery acid everywhere.


While Jet Skis can be an extremely fun activity to do on the water, keep in mind all of the regular maintenance that is needed to keep this fun continuing for many years. Your water vehicle should be treated just as well as your land vehicle even though it might not be used as often.