I found the BCM messes with the charging of the battery and the only way to fully charge the battery is to disconnect from the car and charge on its own, I left it connected to the car and on charge for 3 days and it still hadn't fully charged, it took 18ish hours iirc to charge fully when disconnected from the car with my 6A RING charger, I was leaving it plugged in and it was still reading low on the battery meter on MMI before hand.
__________________
|