How to restore a lawn Mower Battery ( Complete Guide)

Last Modified

March 13, 2023 by Hirah Ehsan

A lawnmower that is equally efficient is needed for lawns that are quite large. For those who wish to maintain their lawns themselves, riding mowers are a good option. Despite the best efforts of its operator, an unpowered lawnmower will not travel far. Most riding mowers run off twelve-volt batteries. These batteries are smaller than those found in automobiles. There are some mowers that use 6-volt batteries instead.

A riding lawn mower’s battery is responsible for cranking the engine when the engine is started, no matter its size. The recharging system of the mower allows the battery to be refilled as soon as the engine is started and running. You will not be able to complete your work if your battery is dead or is not functioning properly.

How to restore a lawn Mower Battery

The following steps will explain how to restore any lawnmower battery.

  1. Removing all caps

The top of the lawn mower battery has battery cells. You will see these when you remove the battery from the lawnmower. On top of each cell will be a cap. Removing the caps requires the use of a flat screw. Keep an eye out for spills, as it’s pretty easy. Your clothing and skin are at risk of burning due to the high level of acid in them. Because of this reason, we proposed safety precautions for this procedure.

  • Taking the acid level into account

Next, you’ll be able to reach the battery acid. Remove the acid gently from the cells with a syringe or dropper after 50 to 60% of the cells have been filled. Once again, be careful to not contaminate the liquid. Don’t over the drain

  • Drain and clean

Sulfate buildup inside lawn mower batteries tends to kill batteries before they reach their life expectancy. We must remove those build-ups of sulfates before we can restore the battery. With our wet towel, we will clean the outer surface.

A wet towel won’t be enough to remove corrosion from the battery terminals if they have corroded. To remove that debris, use sandpaper or corrosion cleaner. Sandpaper between 300 and 400 grit is ideal for this task.

However, to drain the solvent from the battery, you’ll need to turn it upside down. The best place to do this is in an area with good ventilation. Drain the foul liquid into a plastic tub.

  • Distilled water and magnesium sulfate in a solution

In the following step, you will need to prepare a saturated solution containing distilled water and Epsom salt or magnesium sulfate. Using this mixture, thin the soda and water mixture with distilled water over the whole gallon.

Following the preparation of the solution, you will have to use a dropper to apply the solution to each cell. Make sure the mixture reaches every corner of the battery by shaking it for a minute or two. Remove the battery’s solvent once again. Baking soda in the solution cleans up these battery cells in an amazing way.

  • Add electrolyte to battery cells

Charge the battery with the electrolyte supplied with it. Activating batteries with water or other liquids are not recommended. To make Epsom salt baths, mix 4 ounces of Epsom salt with one gallon of warm distilled water. Fill the cell enough with the solution using a funnel. Electrolytes can be filled at 60 degrees Fahrenheit up to 86 degrees Fahrenheit. When the electrolyte is stored in a cold location, it’s best to warm it to room temperature prior to use. According to the indication, fill the battery up to the top level.

  • Charging and cycling.

It’s time to charge your battery. Put the charger on low charging mode or trickle charging mode. Charging for 24 hours with 2 amps is recommended. Battery life usually increases within that timeframe. Using a multimeter and load tester, you can confirm the improvement.

Battery chargers should show 12 volts or more when they’re charging. As long as the load tester is installed, it will be able to reveal whether the battery can be used in a lawnmower and its cranking amp. A battery that cranks at 200 amps is in good shape. In different batteries, cranking amps need to be selected differently. Please see the attached stocker for the correct amp.

After the charging process is complete, disconnect the charger. Repeat this process with fresh distilled water and dispose of the excess. To start the battery cycle, close the lid of the container and use it in the lawnmower.

The moment the battery’s cranking amp falls below a certain level, then it must be stopped being charged. Leave the car lights on and the battery in the car. Testing the battery’s voltage and cranking amps is recommended again.

Material Needed

  • A dropper, syringe, needle, etc.
  • Epsom salt  
  • Partially Damaged lawn mower batteries
  • Charger for batteries Water distilled

Frequently Asked Questions

How long do mower batteries last?

Battery life for a riding lawnmower is approximately four years. You’ll notice that your battery won’t hold a charge for the same length of time once it has reached the end of its lifespan.

If my lawnmower battery is dead, will it run?

Without a battery, many lawnmower features are not available. Assuring that your riding lawnmower’s battery is fully charged before using the mower is easy because they come with a charging system.


Batteries are one of the most important features of a lawnmower. Any fault in them can land you in trouble. You may not be in a position to buy a new battery due to some unknown reasons. But you don’t need to worry about it. Our simple step guide will bring you out of trouble. We have provided enough information to make you restore your battery on your own. We hope so this article will lend you some help.

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