why does my Volkswagen Golf Eighth Generation (2020-present) battery drain overnight

Solution

1. Preparation

• Gather tools: OBD-II scanner, multimeter, socket set, wrenches, and cleaning supplies.
• Ensure the vehicle is parked in a safe area and the ignition is off.
• Disconnect the negative battery terminal.

2. Inspect and Clean Battery Terminals

• Using a wire brush, clean any corrosion from the battery terminals and cable connections.
• Ensure that connections are tight and secure, then reconnect the negative terminal.

3. Replace Faulty Battery (if needed)

• Remove Battery:
  • Disconnect the negative terminal first, followed by the positive terminal.
  • Remove any retaining bracket or straps securing the battery.
  • Carefully lift out the battery.
• Install New Battery:
  • Place the new battery in the tray and secure it with the retaining bracket.
  • Connect the positive terminal first, followed by the negative terminal.
  • Apply battery terminal protector spray to prevent future corrosion.

4. Address Parasitic Draw

• Identify Faulty Circuit:
  • With the multimeter set to measure current (amps), connect it in series with the negative battery terminal.
  • Pull fuses one by one while monitoring the multimeter reading to identify which circuit has excessive draw.
• Repair or Replace Affected Components:
  • Repair any faulty components or wiring that is causing the excessive draw.
  • Reinstall fuses once the issue has been resolved.

5. Verify Alternator Function

• Start the engine and measure the voltage across the battery terminals.
• Voltage should read between 13.8 to 14.4 volts indicating proper charging.
• If the voltage is low, the alternator may need inspection or replacement.