why does my Volkswagen Golf MK7 (2015-2019) have a weak battery after charging

Solution

1. Preparation

• Tools Required: Multimeter, OBD-II scanner, battery load tester, wrench set, terminal cleaner
• Disconnect the negative terminal of the battery to ensure safety while working on the electrical system.

2. Clean Battery Terminals

• Use a terminal cleaner or a wire brush to remove corrosion from the battery terminals.
• After cleaning, reconnect the terminals securely, starting with the positive terminal followed by the negative terminal.

3. Replace the Battery (if necessary)

• Tools Required: Wrench set, battery terminal wrench
• Remove the battery hold-down clamp using the appropriate wrench.
• Carefully lift the old battery out of the vehicle.
• Place the new battery in the battery tray, ensuring it is oriented correctly.
• Reinstall the hold-down clamp and tighten to secure the battery.

4. Test the Alternator

• Start the engine and use a multimeter to check the alternator output.
• If the output is below 13.7 volts, the alternator may need to be replaced or repaired.

5. Inspect Wiring and Fuses

• Check for any frayed or damaged wiring connected to the battery and alternator.
• Inspect all related fuses and replace any that are blown.