How to replace a car battery
Most batteries last 3–5 years. Many modern cars need the new battery to be registered with a scan tool so the charging system adapts to it.
Tools
- Spanners or sockets for the terminals and clamp
- Terminal brush
- Memory saver (optional)
Parts & materials
- Battery with the correct size, terminal layout, capacity and technology (standard, EFB or AGM, especially on start-stop cars)
Step by step
- Note any radio codes and make sure you have the key.
- Switch off the ignition and all accessories.
- Disconnect the negative (−) terminal first, then the positive (+).
- Remove the battery clamp and lift the battery out. Batteries are heavy: lift with your legs.
- Clean the terminals and battery tray.
- Fit the new battery and its clamp.
- Connect the positive (+) first, then the negative (−). Tighten firmly.
- On cars that require it, register the new battery with a scan tool.
- Re-initialise windows, clock and radio presets if needed. Recycle the old battery.
Safety: Always disconnect negative first and reconnect it last, to avoid shorting the spanner to the body.
Symptoms this can fix
Procedures differ between vehicles. Check your vehicle's service information for specifications, torque values and any special steps.