How To Charge A Lawn Mower Battery

If you own a lawnmower, chances are you’ve experienced a dead battery because of how infrequent this piece of equipment is used. Most owners neglect to maintain their battery properly, and, in such cases, knowing how to charge a lawn mower battery becomes critically important.

The 12-volt lead-acid battery on your lawnmower is designed to provide the starting power and can be recharged using a battery charger with a power output of no more than 10-amps. If you don’t have sufficient funds to invest in a battery charger, then you can also use your car to jumpstart your lawnmower.

Choosing the right charger is of prime importance as the lawn battery is needed to maintain a certain voltage and capacity to perform this task. However, when the battery is left on charge during periods of nonuse, it will gradually discharge. Over time the battery will continue to discharge to a point where it loses its ability to start your lawnmower.

Why Charging A Lawn Mower Battery Important?

A dead battery, unfortunately, is only the beginning of your problems as lead-acid batteries discharge and are left unserviceable. It can cause sulfate iron, which is the beginning of the end of your battery. If the battery is not immediately charged, the salvation process will continue and gradually decrease the battery capacity.

Wait too long, and salvation will cause permanent damage to your battery. This is why battery failure is the number one warranty item for all lawnmower manufacturers. Without proper battery maintenance, you can turn a completely new battery into an unsalvageable one within a year.

However, with the proper battery maintenance, you can easily extend the life of your battery by four or even five years.

2 Ways You Can Follow to Charge Your Lawnmower Battery

Essentially, there are two different ways to charge a lawnmower battery, namely:

1. Battery charger
2. Jumpstarting using your car (or similar vehicle)

1. Using a Battery Charger

Investing in a battery charger to do the job for you is a smart choice. An ingenious charger equipped with an intricate schematic interface is capable of communicating with the battery and automatically lowering the charging current as soon as it detects that the battery is about to be 100% charged.

Not only does this great feature help eliminate the risk of unnecessary battery overheating, but it also helps in preventing acid leakage. Acid leakage, according to many professionals, is a sign of battery decay. It can either limit the battery’s ability to retain its energy or damage it permanently.

Full charge detection is one of many great features that won’t be available to individuals who plan to charge the battery of their lawnmower with their cars.

Finding the Right Battery Charger

While deciding on the ideal charger for your lawnmower, it is prudent that you first verify the voltage of the battery to be charged. Most ride-on mowers are equipped with 12V battery to give them the starting power they need. However, it should be noted that lawnmowers manufactured in the early 1980s were equipped with a 6V battery.

Today, most battery chargers available on the market can efficiently handle different voltage ranges. Some have a digital interface, while others have analog interfaces enabling you to choose the appropriate voltage for your battery.

When choosing a battery charger for a lawnmower, choosing a charger with an output power of no more than 10A is of paramount importance, as anything beyond this value can cause substantial damage to your battery.

Connecting the Battery to The Charger

Assuming that you have decided on your battery charger, you would want to follow the steps enlisted below to charge your lawnmower’s battery.

• The first step in charging your battery is connecting it to the charger. (Before making any connections, make sure that the charger is not plugged into an electrical outlet.)
• Raise the seat of your ride-on lawnmower to gain access to the battery. You are welcome to leave the battery in its housing or remove it from the mower. In either case, the charging capacity of the battery is not affected in any way.
• Properly read the charger’s manufacturer instructions and lawnmower manuals before charging.
• Connect the red positive (+) battery terminal to the red charging cable.
• Connect the black negative battery terminal (-) to the black charging cable.
• Finally, use the interface to set the rate of the battery charger to the correct output level and connect it to a power source.

A lawnmower battery should take about 4 to 6 hours to charge fully. Modern chargers may start beeping, or light may illuminate to inform you that charging is complete. Some chargers may shut down completely after they have supplied the battery with full power. You can now disconnect the charger from the power source before disconnecting the battery from the charger.

2. Jumpstarting Your Lawn Mower

These days battery chargers have become reasonably affordable, but still, in a situation where you can’t invest in them, you might consider using your car to crank up your lawnmower. Rest assured that this is an absolutely safe method and that you can charge your lawnmower’s battery reliably without causing it any damage.

The process of starting a lawnmower using the car is almost the same as charging with a battery charger. If you are still confused, follow the steps outlined below in sequence to get started:

1. Lift the seat of your lawnmower to gain access to the battery.
2. Identify the positive and negative terminals in both batteries correctly and connect them accordingly.
3. Try to start the lawnmower. If it works, it is best to let it run for a few hours for its alternator to do the remaining job.

Here is the related article: Can You Jump A Lawn Mower Battery With A Car Battery?

Understanding How Lawn Mower Batteries Operate

The battery used in a lawnmower works in a similar manner as does a car battery. It stores electric power, which is used to start and run the lawnmower. The battery cannot be depleted while in use thanks to its alternator charging unit, which restores used up energy.

Without a properly working alternator, your battery will stop working after each use and might need external charging every time before use.

How Lawn Mower Battery Gets Discharged?

One of the essential parts of a lawnmower is its battery, and maintaining it is a bit like babysitting. You have to ensure that the battery has a certain amount of power in it. You might have forgotten to remove the key from the ignition, thus inadvertently draining your battery, or you might have left your lawnmower lie in storage for a lengthy period.

Take winter, for example. Lead-acid batteries tend to discharge during cold weather slowly. When you try to start our lawnmower, you may get an undesirable result after sticking the key into the ignition and turning it.

This kind of occurrence during the start of the lawn care season is not particularly rare, especially if you left the battery cables connected to the battery while your lawnmower was in storage.

Fortunately, even if your battery is dead as a result of being idle, you can easily get it back working again by recharging it. Here’s a comprehensive breakdown of how you can do exactly that.


Be aware that lead batteries are known to be potentially hazardous, particularly when it’s your first time learning how to charge a lawn mower battery. Experts recommend that you charge all batteries in a well-ventilated area and never neglect wearing personal safety gear such as glasses and gloves.

There may be situations where, even after all your effort, your battery may seem to lose its ability to maintain its energy. In such situations, it is best to replace the battery with a new one, but with similar power rating.