I did end up purchasing a battery charger from the BMW dealer rather than having them install directly to the car. It was recommended by the BMW mechanic and is called the "Advanced Battery Charging System" Part #: 82-11-0-026-663. $69.00 It has a red light and green light the red light blinks when charging and green when full. It is 1.25 amps. Also as Gilbert described has the "official BMW" logo. Peace of mind knowing that this has been verified by BMW and won't over charge the system or damage anything. Thanks for the comments.