Assuming that this is some form of motor vehicle and that you have the charger plugged into the 'cigar' lighter socket...
This is likely to be a re-wire job to pick up a positive 'always-on' feed. Probably not a good idea on such a recent model, for resale (and possibly, safety) reasons.
I mostly charge my mobile (cell) indoors and just top it up when I'm driving, which works out fine on the BMW, although the socket is 'always-on'.
If this is a permanent installation they may have wired it this way because some linked ICE displays, even in 'background' mode, will flatten the battery if left for more than a couple of days.
Robert Johnson, September 2004
