The Benefits of Trickle Charging a Jet Ski Battery

Although most people have some experience with car batteries, new jet ski owners may not know that much about the battery in their jet ski.  Because jet skis aren’t ridden all year, jet ski batteries require some additional maintenance that isn’t required with a car battery.  Specifically, jet ski batteries need to be charged periodically during the off-season.

Can you trickle charge a jet ski battery?

It is best practice to trickle charge your jet ski battery when not in use to extend the lifecycle of your battery. Trickle charging your PWC battery will provide a slow rate of charge to top off your battery when not in use as lead acid batteries can self discharge over a storage period and go bad.

In the past, there were a few ways people could charge their jet skis, but trickle-charging, or smart charging, has become the norm in recent years.  If you’ve heard terms such as a trickle-charger, smart charger, battery maintainer, or battery tender, you may be wondering what the differences are between them, if any. In the past, these were indeed different types of chargers, but most of today’s chargers perform the functions of all of them, which has made them the preferred charger type for jet ski batteries. But what exactly is trickle-charging and what are the benefits of trickle-charging a jet ski?

Trickle-charging simply means charging a jet ski a slow rate of charge rather than a fast one. Today, trickle-chargers have been replaced with smart chargers that have the added benefit of an automatic turn-off switch. Simply attach the battery to the charger and the charger will deliver a slow and steady current until the battery is charged, and then automatically turn off.  As the battery begins to lose power again, the charger will sense the need for an additional charge and turn back on. 

Smart charging/trickle-charging is the best way to charge your jet ski because it requires the least amount of maintenance to maintain your battery during the off-season.  Not only do they charge the jet ski battery at a slow and steady pace that prevents it from draining while not in use or from becoming damaged due to overcharging, but they also turn off and on automatically and often have added features such as automatic desulfation and thermal compensation.

Jet Ski Battery Basics

Before we talk more about the benefits of trickle charging a jet ski battery, it helps to have a basic understanding of jet ski batteries and how they work.


Almost all jet skis come standard with a 12-volt, lead-acid battery, which is the same type of battery as most cars, but they will have a different amperage and size. Never try to put a car battery in a jet ski!  You can also buy what’s known as an AGM battery.

Sea-Doo now makes an upgrade to have dual batteries in a jet ski, this is a great upgrade if you have a stereo, other high battery draw item, or want to ensure your ride always starts.

Most people prefer AGM batteries because they handle cold temperatures and vibration better than lead-acid batteries.  They also require less maintenance. You’ll never have to add more liquid to an AGM battery, whereas you may have to add acid or water to a standard battery. As a trade-off, though, they are usually more expensive and don’t last as long as a lead-acid battery.

Lithium-ion batteries are also becoming more popular in jet skis, but they are less common than either the AGM batteries or lead-acid batteries. Regardless of which type of battery you choose, it will almost certainly be a 12-volt.

Size of Batteries

There are a few different sizes of batteries that jet skis use. Firstly, they will use either a smaller size for a 2-stroke or a larger battery for a 4-stroke as it needs more cranking power to start.  Even if you have a jet ski with a 4-stroke engine, it is still common for many jet skis (especially from Yamaha and Kawasaki) to use a smaller battery designed for a 2-stroke because there just aren’t that many electronic components the battery is needed for.

There are also a few different sizes for batteries (usually a 16, 20, or 30).  The most common 2-stroke size is the EXT16L and the most common 4-stroke size is an EXT30L. It’s important to know what size battery your jet ski takes so that when you replace it, you replace it with the correct size.

If you have problems with dead batteries, you can also upgrade your size to have more amp hours and cranking power.

The Best Battery for a Jet Ski

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.

How Jet Ski Batteries Work

Jet Ski batteries are very similar to car batteries. They are primarily used to create the spark that ignites the engine and also to operate the electrical systems onboard the jet ski, such as depth finders, fish finders, GPS, and stereo systems.  The larger engine size and more advanced computer/electrical systems of many newer jet skis explain why they often have larger batteries now than they did in the past.

Unlike cars, jet skis don’t have elaborate charging systems built-in. Instead of a true alternator, they use what’s known as a stator. The stator works similarly to a trickle-charger, but while you’re operating the jet ski. As a result, to maintain the charge in your battery, you need to ride it fairly often. Riding your jet ski once a week during the high season should be enough to maintain a charge in your jet ski.

When you don’t ride your jet ski for a while, it begins to sulfate and self-discharge unless it is charged with an external charger.  Because jet skis are used seasonally, it’s important that when you winterize your jet ski, or if you won’t be using it for more than a month or so, you remove the battery and regularly charge it.

If you don’t regularly charge a jet ski battery that isn’t being frequently used, it will break down and need to be replaced before the jet ski can be ridden.

How Jet Ski Batteries are Charged

Because jet ski batteries need to be regularly charged, they are removed from the jet ski during the off-season and plugged into a charger that is connected to an outlet, usually in your garage.  (You can also purchase solar chargers, which we’ll talk about later).

If you live in a colder climate, you will want to store the batteries in a garage or basement so you don’t freeze your cells. Always store on a piece of wood or shelf to insulate the battery from a cold concrete floor.

Battery charging technology has come a long way in recent years.  Chargers used to deliver as much power as they could in order to charge a battery as quickly as possible and you’d have to watch the battery very carefully and unplug the charge promptly to ensure the battery didn’t overcharge and break.  To avoid this, trickle chargers and smart chargers were invented.

What is Trickle Charging?

In the past, trickle chargers were battery chargers that would deliver a slow, uninterrupted current to a fully-charged battery at the battery’s rate of self-discharge. This would keep the battery charge stable for an indefinite period. However, in some cases, the constant flow of electricity, when left on for an extended period, would still inadvertently end up overcharging and damaging the battery. 

In recent years, trickle chargers have evolved into smart chargers/battery maintainers.  These chargers still deliver small amounts of electrical current to a battery in order to charge it slowly over time, but they are also able to “read” when the battery is fully charged and will turn off and on as necessary to stop or resume charging as the battery self-discharges. 

Today, if you look for a jet ski battery charger, most of your search results will yield chargers that operate as a hybrid trickle charger/smart charger/battery maintainer. When you purchase a charger for your jet ski battery, these are what you want to buy.

What are the Benefits of Trickle Charging a Jet Ski Battery?

There are many benefits to trickle-charging a jet ski battery, which is why it has become the normal way to maintain a jet ski battery. Tickle-charging is beneficial because it:

  • Prevents the battery from draining when not in use for extended periods (i.e. winter).
  • Prevents overcharging or charging too quickly, both of which can damage the battery, or can even cause a fire.
  • Can be left on the jet ski battery 24/7 without risk of damage to the battery or the release of harmful gasses into the surrounding environment.

In addition to these two primary benefits, today’s smart chargers frequently include added benefits such as:

  • Thermal compensation—the charger will adjust the charging amperage based on the ambient temperature, which affects the rate at which the battery charges.
  • Automatic desulfation—the charger will detect sulfation and repair the battery automatically.
  • Multiple operating modes—most chargers will be equipped to work with a variety of 12-volt batteries, whether they are lead-acid, AGM, or Lithium, so if you upgrade your battery, you won’t have to buy a new charger.

What Type of Charger Should You Buy?

The most important consideration when buying a jet ski battery is to look at the charging rate.  For a jet ski, you should not charge the PWC battery faster than 2 amps per hour, and many people will recommend you try to stick closer to 1 amp per hour.  This means you will be looking for a charger that is labeled with a number around 1A-2A.

The three chargers I recommend are this one from Battery Tender, which charges at .750A, or either the NOCO Genius 1 or NOCO Genius 2, which charge at 1A and 2A respectively. Battery Tender has been around for a really long time and has a great reputation. NOCO does have some really great features like thermal compensation and automatic desulfation.

How to Charge Your Jet Ski Using a Trickle Charger/Smart Charger

When you know you won’t be riding your jet ski for a while, it’s time to charge it. This should always be a part of your winterization maintenance routine. Here’s how to do it:

  1. Remove the battery from the jet ski. This may feel a little intimidating the first time you do it, but it’s not difficult. Most batteries only require a Phillips head screwdriver. You’ll likely have to remove some plastic panels, terminal covers, and a breather hose if your battery has one. Then you can disconnect the terminals.  Be sure to disconnect the black cable first.
  2. If it’s been a while since you’ve looked at the battery, check it for signs of wear or breaking. If you see cracks or leaking fluid, you should probably just buy a new one.
  3. Bring the battery over to a power outlet in a dry, secure, well-ventilated environment such as your garage. Be sure it isn’t near anything flammable.
  4. Use a little baking soda and water to clean any corrosion off the terminals, then thoroughly dry them off.
  5. Make sure the battery charger is NOT plugged into the wall. Then, connect the charger to the battery (most have alligator clips). First, attach the red cable to the positive (+) terminal, then attach the black cable to the negative terminal (-).
  6. Plug in the charger. If your charger allows you to set the charge rate, set it for 1 amp/hour.  Do NOT charge the battery at a rate higher than 2 amps/hour.
  7. Leave it until next season. The smart charger will automatically turn off and on as necessary to maintain the battery’s charge.  (It’s important to remember that this is only true for smart trickle chargers; other types of chargers will not automatically turn off and you cannot leave them attached to the battery once the battery has been fully charged.)
  8. When you go to disconnect the battery from the charger, first turn off and unplug the charger. Then disconnect the cables, beginning with the black, negative (-) terminal, and finishing with the positive, red (+) terminal.
  9. Reconnect the battery, breather hose (if you have one), terminal covers, and access panels to the PWC. You can apply a lubricating spray to the terminals to prevent them from corrosion.
  10. That’s it! You’re ready to start your next season out on the water.

FAQ’s about Charging Jet Ski Batteries

Do you really have to remove the battery from the jet ski before charging it?

Yes, you should remove your battery from your jet ski before charging it. It can be dangerous to attempt to charge the battery while it is still connected to the jet ski as there can be fumes from the fuel tank within the jet ski. Always remove the battery before charging it or you can risk sending too much voltage to your jet skis computer or cause a fire with the fumes.

Can you jump-start a jet ski battery?

You should NEVER try to jump-start a jet ski battery with a car or a truck battery. The power difference will fry the battery or electronics on your jet ski and you’ll have to do some repairs. Though it is technically possible to jump-start a jet ski battery with another jet ski, it is not recommended, especially if you don’t know if the other jet ski has the same kind of battery or not. Luckily, most modern chargers will charge a jet ski battery even if it is totally dead.

Can you use a car or mower battery in a jet ski?

You should not use a car or lawn mower battery on a jet ski. Car, mower, and jet ski batteries are not the same sizes and they don’t have the same amounts of power. If you tried, your jet ski may not start, or you could fry your jet ski’s electronics.

Can you use a car battery charger to charge a jet ski?

You can use a car battery charger to charge a jet ski battery only if it can go as low as 1-2 amp hours charging rate. Many car chargers do not offer amperage this low and you cannot use them to charge a PWC battery. A jet ski battery should never be charged at a rate faster than 2 amps/hour.

How long does it take to charge a jet ski battery?

If you charge a 16 amp hour jet ski battery at 1 amp per hour and the battery is completely dead, it will take about 16 hours. Most of the time, you only need to top it off which may only be 4-5 amp hours which would take 4-5 hours. Ideally, you want to charge your battery as slowly as possible.

How do you charge a jet ski battery faster?

Charging a jet ski battery fast is not recommended. Most jet ski batteries specify a charge rate of 1-2 amps. Charging a jet ski battery takes some time, but even a dead battery will charge to a working level in about 4 hours. If you try to charge a jet ski more quickly by upping the amperage, you will likely damage the battery.

Are there any eco-friendly alternatives for charging a jet ski battery?

There are new solar-powered chargers that are eco-friendly that works very similarly to trickle chargers. They’re a great alternative and you can use them without having to remove the battery from the jet ski. They also work well in all weather conditions and don’t require direct sunlight. If you have your jet ski somewhere without a power connection, this is a great option.


Charging jet ski batteries has come a long way over the years. People used to have to follow a charging schedule during the off-season and watch their chargers very carefully to prevent over or under-charging the battery.  But the invention of smart chargers has changed all that.

Smart chargers that trickle-charge the jet ski slowly over time and have built-in automatic on/off switches have made charging jet skis during the off-season easier than ever.  These chargers take the guess-work out of battery charging. 

Once the high season is over, you just need to remove the battery from your jet ski, plug in the smart charger, hook it up to the battery, and you can basically leave it until you’re ready to use the jet ski again next season.  These benefits coupled with the added features of many new smart chargers make trickle-charging the optimum method for charging your jet ski battery.