Could you please explain why it is a concern? I'd be much more concerned wiring directly to the battery. I've learned over the years to never wire directly to the battery without a relay. The GPS connection is CAN bus controlled and prevents battery drainage. The cigarette lighter type charger I had wired to the same GPS harness had no problems for the past year (BMW GPS harness wired to cigarette adapter to car iPhone USB charger).
I'll give wiring directly a shot but I know with 100% certainty this will make no difference.
Originally Posted by Burnszilla
My connection was wired directly to the battery.
I would be concerned with the BMW GPS connection..
Direct connection to the battery would be the best way to diagnose the problem.