Riding Mower Battery Care: Avoid the Dead Battery Surprise

Every spring, we get a rush of calls about riding mowers that won't start. More often than not, the culprit is a dead battery. A little off-season care goes a long way.

Most riding mowers use a 12-volt lead-acid battery, similar to (but smaller than) a car battery. These batteries self-discharge over time, especially in cold weather. A battery that sits unused for 3-4 months over winter will often be too weak to start the engine.

Prevention is simple: use a battery tender (also called a trickle charger or battery maintainer). These devices plug into a wall outlet and connect to your battery, automatically maintaining the charge level without overcharging. You can leave them connected all winter. A basic battery tender costs $25-35 and pays for itself by extending battery life.

Before storage, clean the battery terminals. Disconnect the negative cable first, then the positive. Use a wire brush or terminal cleaner to remove any corrosion (the white or green crusty buildup). Apply a thin coat of dielectric grease or petroleum jelly to prevent future corrosion. Reconnect positive first, then negative.

Check the electrolyte level if you have a serviceable battery (one with removable caps). The plates should be covered with fluid. Add distilled water if needed — never tap water, and never add acid.

When should you replace the battery? If it won't hold a charge after sitting on a tender, if it's more than 3-4 years old and struggling to start the engine, or if the case is cracked, swollen, or leaking. Most riding mower batteries last 3-5 years with proper care.

We stock replacement batteries for most common riding mowers and can test your existing battery to see if it's still good. Stop by before spring — don't wait until the first mow day to find out your battery is dead.