How to Change a Car Pattery

1. You don't want to spend time and money installing a new battery if the problem is not with the battery itself. Take the following three things into consideration:

Verify that the battery has been given the chance to recharge properly by driving constantly for 30 minutes (with minimal electrical usage, including the air conditioner).

Finally, you should check the alternator. Some cars also have a battery meter, with the engine running, the alternator usually maintains a charge close to 13.8-14.2 volts in a properly functioning charging system. The battery should have 12.4-12.8 volts with the engine off, and with no accessory load.

2. Set up a secure working environment. Park on a flat, level surface at a safe distance from traffic, sparks or open flames. Put on the parking brake. Don't smoke, and make sure any smokers in proximity to the working area know not to smoke as well. Remember that electricity is not the only danger; batteries contain a sulfuric acid electrolyte solution, which is highly corrosive (i.e. can burn your skin) and produces a flammable gas. Put on gloves and safety goggles.

Remove the cigarette lighter and plug the memory keeper into the lighter socket. A Complementary metal–oxide–semiconductor (CMOS) will keep the PIN codes and settings for radios and navigation systems from getting erased when you disconnect the battery. If you don't have a memory keeper make sure you have all the PINs for your electronic equipment before you start. You may wish to check your car manual to see what devices may be affected.

After opening your hood, use the prop rod to keep your hood open (Most newer cars have hoods that hold themselves up.

3. Locate the battery - The battery should be located in an accessible part on either side of the car's frame. The battery is a rectangular box with two cables attached to it. Some European cars (some BMW's) have the battery under the matting in the trunk, or inside the fender of the wheel well (some Chrysler's). The latter is often very difficult to remove.

Locate the positive and the negative terminals of the old car battery. The positive terminal will have a plus sign and the negative terminal will have a minus sign.

Look for sulfate build-up in the form of a whitish or blue residue around the terminal - removing this can sometimes solve issues with a faulty battery. Note: do not touch this powder with your bare hands, as it can often contain dried out sulfuric acid.

Loosen the negative cable clamp with a wrench (Usually 8mm or 10mm) and slide it off of the terminal. If the cables are unmarked, label them so that they don't get mixed up (otherwise you may ruin your car's electric system later on). It is also important that you disconnect the negative terminal socket before the positive terminal socket. Otherwise, you may short circuit the positive terminal to a grounded part of the car.

Disconnect the positive terminal.

Remove the car battery - Unfasten the battery holder and remove any screws, clamps or bars holding the battery in place. Carefully lift the battery out of the car. Remember that a battery can weigh 30 to 60 pounds, or 13.5 to 27 kilos, so if you have any back problems, get a helping hand.

4. Clean the terminal clamps and the battery tray. You can use a baking soda solution and a wire brush. If there's any severe corrosion, consider replacement by a mechanic. Otherwise, let the area dry before moving onto the next step.

Place the new battery where you just took the old battery out, with the positive and negative terminals on the correct sides. Connect all the screws, clamps or bars that may hold the battery in place.

Reconnect the positive and then the negative terminal - tighten the clamps using a wrench. Spray the terminals with lithium grease to prevent corrosion.

Close the hood - Shut the hood of your car firmly and start your car. Check that all the electronic devices are working properly.