If you own a lawn mower, then you know that there is nothing more frustrating than when the battery dies and it won’t start. If this has happened to you, don’t fear! This article will show you how to restore your lawnmower’s battery so that it’s ready for use again in no time.

How Do I Know if My Lawn Mower Battery is Malfunctioning?

A battery that is in need of repair will be unable to hold a charge and will not start the lawn mower. This can be because it has corroded or fallen victim to other environmental factors such as sitting out in cold weather for too long, which happens more often than you might think!

If your batteries are starting to lose their juice faster than they did before, then it’s probably time for them to get replaced by new ones. It doesn’t matter how old they are: if they’re no longer working well enough, then it’s best just replace them with new ones instead of trying to fix them again and again only for the same result.

What You Need to Restore a Dead or Weak Lawnmower Battery

In order to restore a lawn mower battery, you will need:

  • A screwdriver set with flat and Phillips head screwdrivers.
  • A wrench set capable of removing the bolts from your garden tractor’s seat.
  • An old towel or blanket for padding while working on the project.
  • Goggles if you are concerned about flying metal particles during the removal of parts that may result in injury to your eyesight. You can also use sunglasses instead of goggles if it is too dark outside to see well enough without them.
  • A nonmetallic bowl for collecting the bolts, washers, and screws from your lawn tractor parts as you disassemble them.
  • 400 or 300 grit sandpaper
  • Epsom salt
  • Distilled water 1 gallon
  • Multimeter
  • Load tester
  • Funnel

Safety Rules for Battery Restoration

Wear safety glasses.

Avoid touching your eyes while working with chemicals and sandpaper.

Keep the work area well-lit to avoid falls or other injuries from trips in the dark, which can cause a fall if you trip over something in your path of travel.

Drain the Water and Clean the Battery Case

Disconnect the negative battery terminal.

Screw off the positive battery case cover with a flathead screwdriver or wrench, but remember your safety glasses to avoid getting shocked by touching any of the terminals inside.

Pour out all liquid from inside and wipe away as much sediment as possible.

Mix Epsom salt in distilled water at a ratio of one cup per gallon–shake well before pouring into each cell until they are filled about three-quarters full. Push down on the top part of each solution’s surface (battery acid rises to this point) so that it touches the bottom entirely; let sit for five minutes then remove excess liquid using paper towels and repeat several times if necessary.

Mix a small amount of baking soda with water until it forms a paste and applies to the top of each cell cap, as well as any other surfaces that come in contact with electrolyte fluid.

Scrub off the mixture using a toothbrush or similar tool. Allow time for this treatment to soak into corrosion before rinsing thoroughly with distilled water. Repeat if necessary, then allow the case to air dry completely before reassembling your battery or moving on to the restoration steps below. You can use an air compressor set at low pressure instead of allowing it to air dry, but be careful not to damage rubber seals around caps during the drying process by blowing hard against them!

Also Helpful Articles

How to Care for Lithium-ion Batteries for Garden Tools

What Type and How Much Oil You Need for Your Lawn Mower

How to Clean a Carburetor on Your Push Mower

How to Sharpen Push Lawn Mower Blades

How to Remove Excess Oil From Your Lawn Mower


Pour Electrolyte Fluid into Battery Cells

Once the battery case is clean, open it up and remove any dead or weak cells. Using distilled water instead of tap water will help to reduce corrosion in your newly cleaned case. Be sure not to overfill! Fill each cell with electrolyte fluid until there are about three-quarters full (leave room for expansion). You may also need to fill a reservoir attached between adjacent cells, this can be done using an eyedropper or syringe after removing its cap carefully so as not to damage rubber o-rings which prevent leakage. This process can take some time if you’re adding liquid one drop at a time, especially when working on smaller batteries that contain fewer total cells overall.

Charge and Cycle

After filling with fluid, you’ll need to charge the battery. A car-battery charger that allows for varying amperage outputs will typically be best suited for this task if available, these can often be purchased relatively cheaply at automotive parts stores and allow you to set the desired charging rate (i.e., amps). For small batteries like those used in lawn mowers or motorcycles, there are also specific motorcycle trickle chargers that help ensure maximum efficiency by constantly monitoring your battery’s condition as it charges—often through the use of an integrated digital meter displaying current voltage levels! If neither is available, then any device capable of increasing electrical resistance within the circuit should suffice provided its output rating exceeds that of your original appliance cord/plug.

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