How to Change a Car Battery

No matter how well your vehicle is working, if your battery dies and can’t be recharged, you’re stranded in a vehicle that you can’t drive in for service. You need to know how to change a car battery.

A battery usually has a sticker on it that shows when you bought it and how long you can expect it to survive. To prevent being stuck on the road with a dead battery, enter that information in your owner's manual and have the battery replaced before it comes to the end of its life expectancy.

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Battery jumper clamped to a dead battery

Pull your gear together — an adjustable wrench, a couple of clean lint-free rags, a pair of disposable latex gloves, some water and baking soda, a battery brush, and an inexpensive pair of safety goggles. These steps walk you through how to change a car battery:

1. Turn off your engine.

   Make sure that your vehicle is in Park, with the engine shut off and the parking brake on.

2. Open the hood and place a blanket or pad over the fender.

   This protects your car from corrosive battery acid.

3. Remove the cables from the battery terminals.

   Look in your owner’s manual to see whether your vehicle has negative ground (most do). If it does, use an adjustable wrench to first loosen the nut and bolt on the clamp that holds the battery cable on the negative terminal. (That’s the post with the little “–” or “NEG” on it.) If your vehicle has positive ground, loosen the cable with “+” or “POS” on it first. Remove the cable from the post and lay it out of your way. Then remove the other cable from its post and lay that aside.

   If you have trouble loosening the bolt, grab it with one wrench and the nut with another, and move the wrenches in opposite directions. In this case, you don’t want to remove the bolts; just loosen them enough to release the cable clamps.

4. Remove whatever devices are holding the battery in place.

   When you’re removing a bolt or screw, after you’ve loosened it with a tool, turn it the last few turns by hand so that you have a firm grip on it when it comes loose and it doesn’t drop and roll somewhere you cannot find it.

5. Remove the battery.

   When the battery is free, lift it out of its seat and place it out of your way.

6. If the tray on which the battery was standing is rusty or has deposits on it, clean it with a little baking soda dissolved in water.

   Wear your gloves because the battery stuff is corrosive, and be sure the battery tray is completely dry before taking the next step!

7. Place the new battery on the tray.

   Make sure it is facing in the same direction as the old one was.

8. Replace the devices that held the old battery in place.

   Try to wiggle the battery to make sure it’s completely secure.

9. Replace the battery cables on the terminals in reverse order from which you removed them.

   If your vehicle has negative ground, the positive cable goes back first. Make certain that the clamps holding the cables on the battery terminals are gripping the posts tightly.

10. Take the old battery to a recycling center that accepts batteries.

    Batteries are filled with a toxic, corrosive liquid and must be disposed of properly. What’s more, old batteries are usually rebuilt into new ones, so just throwing one in the trash is doubly bad for the environment. If you have your new battery installed when you buy it, the shop will recycle the old one for you. They’ll probably want to charge a few dollars for this service, but try to negotiate it into the price. You also can call your local recycling center for a referral.