Same problem and the solution was the alternator. Seems the OEM alternator was not putting out enough current to recharge battery and over time battery drain was inevitable. Following installation of new alternator by the service department, deep cylce recharge of the battery, diagonostics of all electrical systems to monitor amp usage, the X5 is ready to go again. Don't know if others that have experienced high battery drain have implemented this solution, but I would check with your service department as it fixed our ride.