why does my BMW 5 Series G30/G31 (2017-2024) battery die after a few days

Solution

1. Battery Replacement

1. Preparation:
   • Gather tools: Socket set, torque wrench, battery terminal cleaner, and safety gloves.
   • Ensure the vehicle is off and parked in a safe area.
2. Remove Negative Terminal:
   • Using a socket set, loosen the negative battery terminal and disconnect it first to avoid short circuits.
3. Remove Positive Terminal:
   • Loosen and remove the positive battery terminal.
4. Remove the Old Battery:
   • Unfasten any battery hold-downs and carefully lift the battery out of the tray.
5. Clean Battery Tray:
   • Clean any corrosion or debris from the battery tray using a battery terminal cleaner.
6. Install New Battery:
   • Place the new battery in the tray and secure it with hold-downs.
7. Reconnect Terminals:
   • Connect the positive terminal first, followed by the negative terminal. Ensure they are tight.

2. Parasitic Drain Repair

1. Identify the Source:
   • If parasitic draw is detected, turn off all accessories and close doors. Then, reconnect the negative terminal and monitor the ammeter for draw.
2. Check Fuses:
   • Remove fuses one by one to identify which circuit is causing the drain.
3. Repair or Replace Faulty Components:
   • If a faulty component is identified (e.g., a module or accessory), repair or replace it accordingly.
4. Recheck Parasitic Draw:
   • After repairs, measure the current draw again to ensure it is within the acceptable range (typically below 50 mA).