Thanks....also came across this post:

there is something wrong in your car. normally all systems are shut down
in a 15-30 minutes period after locking the car. even the ipod will be turned off...
is your radar detector wired to the car electric system (hard wired) ?
Yes it is as you post in the other thread. and you took power from the next suitable cable around, aha. In aviation this is called hot wired meaning when the device is on it will remain on even you shut off the rest of the systems. In your case the V1 thing blocks the shut down procedure of your car as the BMW controllers can´t shut off the detector and so the systems will stay alive (CD players included) and kill your battery !!!
Better get this "rebuildt" in your BMW shop. The bus system of the E70 is a totally new one, so you have to be very carefully when you try to bring non BMW approved stuff in.