My Audi A6 C6 always shows (through MMI) that my battery level is 100% despite if it's almost empty. Wondering how does it work? Does it only checks the voltage of the battery? If so wouldn't it be 100% whenever the engine is running? Maybe anyone knows what can be wrong because I see 100% even if the engine is stopped.
I found the answer in this manual.
Basically, the Battery Management Control Unit uses:
- current draw on the battery (measured at the control unit)
- temperature of the battery (measured at the control unit and transformed by algorythm to what the actual battery temperature should be)
- voltage of the battery (measured at the positive terminal)
- operating times
The software then makes an elaborate calculation to determine the battery's state of charge. If you are always at 100%, I would suggest that either your battery management control module is defective, or one of the sensors is defective.