How To Restore a Lawn Mower Battery? {A Complete Guide!}

This post may contains affiliate links. If you click and buy we may make a commission, at no additional charge to you. Please see our disclosure policy for more details.

Large lawns require a useful lawnmower in its category. Rowing mowers are an excellent alternative for individuals who desire to maintain their lawns.

Despite the operator’s best efforts, a lawnmower with no power source will not go very far. Most riding mowers need batteries with a voltage of twelve volts.

These batteries are far more compact than those typically used in autos. Rather than 12-volt batteries, some mowers may run on 6-volt batteries.

Regardless of the size of the engine, the battery in a riding lawn mower is the component that cranks it when the engine starts. The lawnmower has a mechanism for recharging the battery.

As soon as the engine is turned on and running, it recharges the battery. If your battery has died or is not performing as it should, you cannot do the task that you have been given to do.

How to Restore a Lawn Mower Battery?

How to Restore a Lawn Mower Battery
Image Source: thecleverhomeowner

The techniques outlined here will show you how to revive the battery of any lawnmower.

Step 1: Remove All Capitalization

Remove All Capitalization
Image Source: knowhow.napaonline

The battery cells are on the top of the lawn mower’s battery. These parts are visible when the lawnmower’s battery is removed.

Keep an eye out for spills since it’s easy to happen because of the high acid concentration. If it happens, your clothes and your flesh may burn.

Step 2: Take into Consideration the Amount of Battery Acid

Take Into Consideration the Amount of Battery Acid
Image Source: rxmechanic

You will then be able to get the battery acid. After 50-60 percent of the cells have been filled, remove the acid from the cells in a careful manner. You can do it by using a syringe or dropper.

Remember to use extreme caution so that you do not taint the liquid. Be careful not to clog the drain.

Step 3: Drain and Sterilize

Drain and Sterilize
Image Source: blog.amsoil

The accumulation of sulfate inside the lawn mower batteries causes the batteries to die before they reach their expected lifespan. Before we can recover the battery, those sulfate deposits accumulated need to be removed.

If the battery terminals have been corroded, removing the corrosion using a cloth that has been dampened with water will not be sufficient. Sandpaper or corrosion cleaner may remove the dirt off the surface.

Sandpaper with a grit rating between 300 and 400 is the best option for this job.

However, you will need to invert the battery so the solvent may escape. You can do it by holding the battery in an inverted position.

You can then drain the putrid liquid into a container made of plastic. The location with the optimum ventilation is the one that you should choose for this activity.

Step 4: Use a Solution Made Up of Distilled Water and Magnesium Sulfate

Use a Solution Made Up of Distilled Water and Magnesium Sulfate
Image Source: camachem

In the next stage, you will need to make a saturated solution using distilled water, Epsom salt, or magnesium sulfate. This solution should be as saturated as possible.

Using this combination, dilute the soda and water mixture you created with one gallon of distilled water.

After preparing the solution, use a dropper to apply it to each cell. These battery cells benefit tremendously from having baking soda in the cleaning solution.

By shaking the battery for a minute or two, you can ensure that the mixture penetrates every crevice of the battery. Take another step to remove the solvent from the battery.

Also Read:- How to Adjust Lawn Mower Height For Better Mowing?

Step 5: The Electrolyte Should be Poured Into the Battery Cells

The Electrolyte Should be Poured Into the Battery Cells
Image Source: energicplus

To charge the battery, use the electrolyte that comes with it. Charging batteries using liquids such as water or other substances is not advisable.

To prepare baths with Epsom salt, use one gallon of warm distilled water with four ounces of Epsom salt and mix well. An adequate amount of solution should be poured into the cell using a funnel.

Electrolytes may be reconstituted at temperatures ranging from sixty to eighty-six degrees Fahrenheit.

Before using the electrolyte, it is in your best interest to bring it up to room temperature if it has been kept in a relaxed environment. Bring the battery level up to its maximum capacity using the signal.

Step 6: Charge it

Charge It
Image Source: thecleverhomeowner

It’s high time you gave your battery a charge. Adjust the charger so it only produces a trickle charge or a low energy level. It is advised to charge for twenty-four hours at a rate of two amps.

Within that period, the average improvement in battery life may be expected. You may demonstrate the progression of the progress by using a load tester and a multimeter.

As long as the load tester is connected to the battery, it will be able to determine whether the battery is suitable for usage in a lawnmower and the amount of cranking amps it produces.

When evaluating the health of a battery, look for one that can crank at 200 amps.

When using various types of batteries, the cranking amps setting must be adjusted appropriately. Regarding the amp, kindly refer to the stocker that has been attached.

After the charging procedure has been finished, you should unplug the charger. This procedure uses new distilled water and removes any leftover liquid.

Put the lid back on the container and put it to use in the lawnmower to get the battery cycling process started.

Suppose the cranking amp of the battery drops below a specific level. In that case, the charging of the battery must be halted immediately.

Don’t forget to turn the lights in the vehicle on and don’t take the battery out. Again, checking the voltage of the battery and the cranking amps is advisable.

Also Read: How To Make A Riding Lawn Mower Go Faster? (7 Possible Ways)

The Required Components

  • A dropper, syringe, needle, etc.
  • Epsom salt
  • Batteries for lawn mowers that are just partially damaged
  • Charger for batteries
  • Water distilled


If you follow these simple instructions, you’ll have your lawn mower’s battery charged and ready to go in no time.

  • You’ll need a set of pliers, distilled water, and a battery charger to complete this step.
  • Take the battery out of the lawnmower, which is the next step in the process. In most cases, you can accomplish this by just unscrewing the lid of the battery and pulling it out.
  • Remove the batteries first, then determine how much liquid remains in the bottle. If it is not complete, add additional distilled water to get it up to the appropriate level.
  • At this point, you must charge the battery. Connect the charger, and then wait for it to finish for roughly 8 hours after you’ve done so.
  • Once you charge the battery completely, replace it in the lawn mower and secure the lid with the screws.

And that wraps things up! You have been successful in recharging the battery in your lawn mower.


How long do the batteries in lawnmowers typically last?

The battery’s life expectancy in a riding lawnmower is roughly four years. After it has reached the end of its lifetime, your battery will no longer be able to maintain a charge for the same time as before.

Will my lawnmower still work even if the battery is dead?

Many of the lawnmower’s functionality is inaccessible if it does not have a battery. Because riding lawnmowers often come equipped with a charging mechanism, it is simple to check that the battery on your mower is ultimately charged before using the machine.

How Long Does a Lawnmower Battery Typically Last?

The battery in a lawnmower may last for up to three years. But it is contingent upon the battery’s use and care.

Can a lawnmower battery cause an electric shock?

Yes, the lawnmower or the charging plug might provide an electric shock if handled while wet. It is potentially dangerous and perhaps deadly. Using a lawnmower or taking the batteries for a lawnmower might cause an electric shock if water comes into contact with the terminals.

Should I Fill the Battery of My Lawn Mower with Water?

You can, but only distilled water will do. Use distilled water rather than tap water, which may cause chemical reactions in the battery. Battery charge retention may be lowered due to minerals in municipal water supplies.


Reconditioning the batteries in your lawn mower is an excellent method to save money and save from throwing away a valuable component.

It is not a very difficult task, and if you have the correct tools and are willing to put in a little effort, you can make your battery last for many more years. If you take the time to maintain your batteries correctly, you may be able to avoid the need for this.

Still, if you notice it is not operating as well as it once did, you should try restoring it.

Leave a Comment