How to Change a Lawn Mower Battery

When it is time to mow the grass, you want your lawn mower to be in good working condition. Your lawn mower may have a lead acid battery or a nickel cadmium battery. Although they are both rechargeable, they will still need to be replaced on occasion. The best way to find out is to check the operator's manual for your model. If your lawn mower is running slowly or strangely, it simply might be time to change the battery. Follow these steps.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• New battery
• Toothbrush
• Rag
• Adjustable wrench
• Stiff wire brush
• Baking soda
• Water

1. Switch the key in your lawn mower to the "Off" position. Turn off any lights or other electrical devices.

2. Locate the battery. Remove the tie-down strap, if any, or unscrew the holding bar that covers it.

3. Check the positive and negative terminals for corrosion. Scrape any corrosion off the cables by using a stiff wire brush, or mix baking soda and water to make a paste.

4. Dip a toothbrush into the paste and scrub the corrosion off the battery terminals and cable ends if they are badly corroded.

5. Rinse and wipe off with a rag.

6. Loosen the negative cable clamp (marked with a minus sign) using an adjustable wrench.

7. Slide the clamp off the battery terminal.

8. Loosen and remove the positive cable clamp (marked with a plus sign).

9. Pull the old battery up and out of the metal box holder.

10. Place the new battery into the metal box holder.

11. Replace the cable clamps over the terminals and tighten with the adjustable wrench, making sure that the negative cable end is on the negative side of the battery.

12. Replace the holding bar or tie-down strap and tighten.

Tips & Warnings

• The positive battery terminal is always larger than the negative battery terminal. Nickel cadmium batteries must not be charged until they are completely discharged.
• Do not use your lawn mower without securing the battery down in the holder.