I must agree there is prob a li-ion battery inside, but it is also possible to charge something without a physical + and - terminal, prob using condition or even induction maybe?
Just for the record... I recently had a problem with my car that resulted in a complete engine strip down and rebuild.... While it was stripped I asked them to make sure they cleaned the EGR valve, and they reported back to me that it was that caked in soot it was wedged open and must have been for some time. I didn't have any problems running up to the swirl flap incident which = the rebuild.
I have to agree with Dabs, I have driven one a 4.4 I think, and been a long distance passenger. Im not a fan at all, 5 series all the way.. Sorry Chris.