Originally Posted by WW08M3vrom
Would leaving my iPhone USB plugged in w/out phone wear down the battery?
No. Car goes to "sleep" approx. 15 minutes after shut down/doors locked and that cuts power to all outlets in the vehicle. USB cable or even an iPod will not draw any power sitting in the car. I have a dedicated iPod that stays in the center console and have never had an issue with the battery in either the M3 or my previous two E60's...