I have a 02/325XI.
The issue is I'm getting low power to start the car. With boosting it starts fine. Also, when I recharge the battery it starts fine but I can not restart it. Battery voltage at no load is 11.8VDC when car is off. Load test, when car is on at 2000RPM and battery is fully charged and all lights, fan and rear defroster are on is 14.1VDC. Also voltage regulates at 14.1VDC at up to 3000rpm that I tested (with load). Alternator belt is new and seems tight.
Although battery is showing 11.8VDC and I cannot start the car but battery indicator is still green. The green indicator is about an inch or so bellow the indicator glass.
When I shut down the car, with the voltmeter at the battery poles I can see the voltage drops from 13.2VDC (car is on at idle and no load) to about 11.7VDC and few seconds after when the fans stop, goes up and stays at 11.9VDC but I can not start it.
Any idea what is going on? Is my battery gone bad?
How can I check if I have any drainage?
Thanks for all the help in advance.