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Your Car: How Do I Maintain My Car Battery?

Learn how to help your car battery lead a good life.

Almost as soon as they’re built, car batteries begin to die. “They’re made with corrosive materials,” says engineer Lee Walker of the Argonne National Laboratory in Illinois. “And that’s their downfall.”

Your standard 12-volt battery contains thin lead plates in a mix of water and sulfuric acid called electrolyte. Lack of use, temperature extremes, and other factors can cause large, unwanted crystals to form in a process called sulfation, the main culprit behind weak and failed batteries.

You can keep sulfation at bay by running your car regularly. If it does catch up with your battery, your mechanic might be able to correct it with a desulfator, a device that emits high-voltage pulses to break down those big crystals.

You should also ask your mechanic to inspect your battery regularly for corrosion of the terminals and low liquid levels.

If your car sits unused for long periods, a tender—a device that plugs into an ordinary AC outlet—will preserve the battery by trickling energy into it. Just be sure it has the proper voltage limits. Extreme overcharging is damaging and, as Walker puts it, can make a battery “rapidly deconstruct”—in other words, explode. So charge on, with care.

AAA technicians can test your car battery and, if needed, replace it on the spot at a $25 discount. For information, call (800) 222-4357 or visit


This article was first published in May 2010. Some facts may have aged gracelessly. Please call ahead to verify information.