Car Battery Replacement — DIY Guide

Battery replacement takes 20 minutes and requires only a wrench. Most batteries last 3-5 years; replace yours before it leaves you stranded.

Symptoms

Park and turn everything off: Make sure the engine is off, key removed, and all electronics (lights, radio) shut down.
Disconnect the negative terminal first: Always negative (black, marked -) first. This prevents short circuits if your wrench touches the body. Loosen the clamp and lift the cable off.
Disconnect the positive terminal: Now the positive (red, marked +). Tuck both cables to the side so they don't touch the battery.
Remove the battery hold-down: Most batteries have a clamp or bar holding them in place. Remove it.
Lift out the old battery: Batteries are heavy (30-50 lbs). Use the strap if there is one, or grip both ends.
Clean the terminals and tray: Use a wire brush on the terminal clamps. Wipe the tray clean — corrosion ruins new batteries.
Install the new battery: Set it in the tray with terminals on the same side as before. Reinstall the hold-down.
Connect positive first, then negative: Reverse of removal. Tighten clamps firmly but don't strip them. Apply a thin coat of battery terminal grease to prevent corrosion.
Start the car and reset accessories: You may need to reprogram radio presets and re-learn power window settings (hold the up button for 5 seconds at the top).

Disconnect negative first to avoid sparks
Wear safety glasses — batteries contain acid
Take the old battery to any auto parts store for free recycling and a small core refund

3-5 years typically. Hot climates shorten battery life faster than cold.

Yes, unless you use a memory saver (small device that plugs into the OBD2 port and powers the car's memory while the battery is disconnected).

Match the group size and CCA (cold cranking amps) of your old battery. Group size is printed on the case.