How to Change a Car Battery

Always replace a car battery with one that's made for your car's make and model. Check your owner's manual for the right voltage and size you'll need. Once you've got your new replacement battery, make sure the vehicle is immobile and in a safe place before you try to change the battery.

• Put the car in park and engage the emergency brake.
• If the vehicle is on an incline, place a wheel chock or wooden block behind the vehicle’s tires.
• If the car is in a garage, make sure the garage door remains open.

Open the vehicle’s hood to locate where the battery is. (Many foreign vehicles have the car battery in the trunk.) If you have difficulty locating the battery, consult the owner’s manual.

• Before you change a car battery, always make sure the engine is cool enough for you to safely work in that area.
• Look for the car battery terminals. They connect to the battery’s positive and negative posts. The positive terminal in most cases has a red cover and is connected to the post on the battery that is stamped by a plus sign. The negative terminal is connected to the post on the battery that is stamped by a minus sign.

Always remove the negative terminal first when changing a car battery.

• Use a socket wrench to loosen the nut on the black, or negative, terminal. Most ratchet and socket sets have a socket size that fits the bolt of a battery terminal.
• Remove the negative terminal from the battery.
• Repeat the process with the red, or positive, terminal.

Use a socket extension if needed to remove the clamp that holds the battery in place. There might be several clamps, so inspect the outside of the battery carefully.

• Set the clamps and fasteners aside and remove the battery from its tray.
• Wear work gloves to replace a car battery. It can be heavy (between 40 and 60 pounds). Keep your hands steady to avoid jostling the battery. Safety glasses are advised as protection against splashing battery acid. If the battery has a handle, use that to lift the battery out.
• If the battery is hard to remove, you can use a battery terminal puller. Do not use tools to try to pry up the cable as it may cause damage. Never allow a metal object to touch both ends of the battery.
• Use a bowl or magnetized plate to collect all the loose pieces as you are changing a car battery. This will prevent them from falling into the car.

Corrosion can damage the battery terminals over time. Greenish residue on the terminals indicates corrosion. Clean the terminals as part of the task of changing a car battery.

• Use a wire brush and a solution of baking soda and water to clean the battery tray and terminals. Dry everything completely.
• Do not install a car battery if there are any damp parts.

Before you replace a car battery with the new one, remove the red and black plastic covers on the ends of the posts of the replacement.

• Prepare your new battery for use by installing anti-corrosion washers on both battery posts. Spray the car’s terminal ends with anti-corrosion solution or apply a corrosion-resistant gel to the terminals.
• Place the new battery in the battery tray, aligning the red (positive) and black (negative) ends of the battery with the matching terminals.
• Re-install the clamp(s) the same way you removed them to secure the battery.

• Connect the positive terminal first. Attach the red (positive) terminal to the positive battery post. Tighten the terminal with a wrench.
• Repeat the process with the black (negative) terminal.
• Try to move the battery around to ensure that the connections on both ends are secure.
• If the battery shifts, check all the clamps and the tightness of the cables.
• If the battery was originally covered, reinstall its cover the way it was removed.
• Close the hood and start the car.
• If the car still doesn't start after changing the battery, have it checked by a certified auto service technician.

The most common temporary solution for a dead car battery is to recharge the battery using another one as a power source. The battery gets just enough power for a trip to the auto parts store. A car battery charger is designed for this purpose, but it is commonly done with jumper cables and a second car.

Follow these steps for jump starting a car battery:

• Position the car with the good battery next to the car with the dead battery. They should be close enough for the jumper cables to reach, but the vehicles should not touch each other.
• Attach the clamp of one end of the positive cable – the red cable – to the positive terminal of the dead battery.
• Connect the clamp of the other end of the positive cable to the positive terminal of the good battery.
• Next, clamp one end of the negative cable – the black cable – to the negative terminal of the good battery. Attach the other end of the negative cable to the engine block of the car with the dead battery.
• Start the car with the good battery that provides the electricity.
• Turn the ignition key (or press the ignition button) of the car with the dead battery. If it starts, let the car run for about 20 minutes to allow for a recharge.
• Disconnect the jumper cables in reverse order.