Most drivers don’t think about their car battery until it is too late. That’s probably why battery failure is the chief cause of road emergencies.
Most batteries today are sealed. However, if yours is not, remove the caps and check the water level every 3 or 4 months. If the level is low, add tap water until it comes up to the bottom of the cap hole. If the tap water in your area is hard, use distilled water.
Tightening and cleaning – Inspect the brackets that hold down the battery. If they are loose, the battery can vibrate, shortening its life. Tighten as necessary. If the brackets are corroded; clean them with a wire brush and spray them with aerosol penetrating solvent. If corrosion is severe, replace the brackets.
Disconnect the battery terminals, lift out the battery, and inspect the tray. Brush off any corrosion and apply a coat of acid-resistant paint. Remove the tray if corrosion has weakened it. Some trays are bolted in, but most are welded and must be chipped out with a cold chisel. Vinyl-coated replacement trays are sold at auto parts stores. To install one, drill holes in the part the old tray was attached to, lining them up with the holes in the replacement tray. Bolt the new tray into place.
Caution: Car batteries contain acid. When working on one, remove jewelry and wear goggles, gloves, and heavy clothes. If acid gets on your skin or in your eyes, rinse for 15 minutes with cold running water. Then get to a doctor. Batteries also emit explosive gas. Never light a match, cause a spark, or smoke near one.