How to Change a Car Battery

Difficulty: Beginner Time: 20–40 minutes

Replacing a car battery is one of the easiest repairs you can do yourself, and it can save you a shop fee. On most cars it takes about 30 minutes with a wrench and a little care.

The one thing you must get right is the order of the cables: take the negative off first and put it back on last. That keeps you from causing sparks if a tool touches metal on the car.

What you'll need

Step by step

1. 1

   Get the right battery

   Batteries come in different group sizes. Look up your car at the parts store or check the label on your old battery so the new one fits the tray and the terminals are on the correct sides.

2. 2

   Park, turn everything off, and find the battery

   Park on level ground, set the parking brake and turn off the engine and all lights. Most batteries are under the hood, but some cars keep them in the trunk or under a seat; your owner's manual shows where.

3. 3

   Disconnect the negative (–) cable first

   The negative terminal is usually black and marked with a minus sign. Loosen its nut and twist the cable off the post. Tuck it aside so it cannot spring back and touch the battery.

4. 4

   Disconnect the positive (+) cable

   The positive terminal is usually red and marked with a plus sign, often under a plastic cover. Loosen it and remove the cable.

5. 5

   Remove the hold-down and lift out the old battery

   Unbolt the bracket or strap that holds the battery in place. Batteries are heavy (30–50 lb), so lift with your legs and keep it upright.

6. 6

   Clean the cable ends and tray

   Scrub white or green corrosion off the cable clamps with a wire brush. A mix of baking soda and water neutralizes acid residue; wipe it dry afterward.

7. 7

   Set the new battery in place and secure it

   Put the new battery in with the terminals facing the same way as the old one. Reinstall the hold-down so the battery cannot move; a loose battery can be damaged by vibration.

8. 8

   Connect the positive (+) cable first

   Attach the red positive cable to the positive post and tighten it until it cannot twist by hand. Put the plastic cover back on.

9. 9

   Connect the negative (–) cable last

   Attach the black negative cable and tighten it. A small spark when it touches is normal. Give both cables a tug to make sure they are tight.

10. 10

    Start the car and check

    Start the engine and make sure the dashboard lights go out normally. You may need to reset the clock, radio presets or power windows' auto-up feature.

Tips

• Take the old battery back to the store when you buy the new one. Most stores charge a refundable "core" deposit and recycle the old battery for free.
• Many parts stores will test your old battery, alternator and starter for free. If the battery tests good, the problem may be elsewhere.
• Some newer cars, especially many European models, need the new battery registered with a scan tool. Check your manual before you start.

Parts and tools that may help

Enter your year, make and model on the store's site to see parts that fit your car.

Car batteryPick up or ship · Advance Auto Parts

Jump starter packPick up today · Advance Auto Parts

Battery chargerPick up today · Advance Auto Parts

Battery terminal cleanerPick up or ship · Advance Auto Parts

MultimeterPick up today · Advance Auto Parts

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Frequently asked questions

Which battery cable do I take off first?

Always disconnect the negative (–, usually black) cable first and reconnect it last. That way, if your wrench touches metal on the car while you work on the positive side, it can't cause a short.

How do I know if I need a new battery?

Slow cranking, clicking when you turn the key, needing jump starts, or a battery older than about 4–5 years are the usual signs. A free battery test at a parts store will tell you for sure.

Will I lose my radio settings?

Often, yes. You may need to reset the clock and radio presets. A plug-in memory saver keeps them while the battery is out, but it is optional.

What do I do with the old battery?

Return it to the store where you buy the new one. Car batteries must be recycled, and most stores refund a core deposit when you bring the old one back.

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