My vehicle is a 4.8 too.....the dealership told me that all the factory options* on the car causes a heavy electrical draw and hence the need for the occasional trickle charge (and yes my battery and "intelligent" sensor have been replaced. Every time I take it in they put it on an electrical discharge meter for days to determine what is causing the excessive draw. As one might imagine in this situation it is a moving target.

What frustrates me the most is that BMW has put me in this ethical dilemma. I can trade the car to a dealership and get screwed on value or I can sell the car privately (with the warranties) and make thousands more but are dumping a problem car on a poor soul (not good karma). It just isn't right!


*options: cold weather, technology, rear climate, 3rd row seating, sport, heads up display, premium sound, comfort seats, comfort access, tighter steering ratio