my Volvo XC90 battery dies overnight, what could be causing this

Solution

1. Preparation

• Gather necessary tools and parts.
• Ensure the vehicle is parked on a flat surface and the engine is off.
• Wear safety gloves and goggles.

2. Disconnect Battery

• Use a socket wrench to disconnect the negative battery terminal first.
• Then, disconnect the positive battery terminal.

3. Clean Battery Terminals

• Remove corrosion from battery terminals using a wire brush and a mixture of baking soda and water.
• Rinse with clean water and dry thoroughly before reconnecting.

4. Test and Replace Battery

• If the battery is not holding a charge (voltage below 12.4V), replace it with a new one.
• Ensure the new battery matches the specifications of the original.

5. Check Electrical System

• Reconnect the battery terminals, starting with the positive terminal followed by the negative terminal.
• Inspect and replace any faulty fuses or relays that were identified during diagnostics.

6. Verify Alternator Function

• Start the engine and measure the voltage at the battery. It should read between 13.7V and 14.7V if the alternator is functioning properly.
• If the voltage is low, consider replacing the alternator.