my Volkswagen Golf battery dies when parked what could be causing this

Solution

1. Preparation

• Gather necessary tools and parts.
• Disconnect the negative battery terminal to prevent electrical shorts.

2. Clean Battery Terminals

• Use a wire brush or terminal cleaner to remove corrosion from the battery terminals.
• Reconnect the terminals securely and ensure they are tight.

3. Address Parasitic Draw

• If a parasitic draw is identified:
  • Inspect and repair or replace the faulty component causing the draw.
  • For example, if the trunk light remains on, adjust or replace the switch.

4. Replace the Battery (if necessary)

• If the battery is found to be defective (e.g., unable to hold charge):
  • Remove the old battery by disconnecting both terminals (negative first).
  • Install the new battery, connecting the positive terminal first, followed by the negative terminal.
  • Ensure the battery is secured in its tray.

5. Test the Alternator

• Start the vehicle and measure the voltage at the battery terminals; it should read between 13.7 to 14.7 volts.
• If the alternator is not charging properly, replace it.