Two problems related to battery have been reported for the 2006 BMW 325. The most recently reported issues are listed below.
The contact owns a 2006 BMW 325i. The contact was driving with the cruise control activated at 76 mph. An abnormal noise was heard from the vehicle as the electrical components failed and the vehicle stalled without warning. The vehicle was towed to the dealer who advised that the battery safety terminal failed. The dealer was unable to provide a cause for the failure. The manufacturer was notified who advised that they would send a representative to further inspect the vehicle. The contact was awaiting further diagnosis of the failure. The failure mileage was 50,000.
BMW doors will not open when locked if electrical power is lost. In case of accident, BMW has an explosive device that separates the battery from the electrical system. Once power is lost, the door handles will not operate to open locked doors and the electrical windows will not work trapping passengers inside. I discovered this when a fuse, #52 on a 2006 325i, blew and the door would not open. Luckily one door was unlocked in the back and my daughter had to climb into the back seat to get out. Advise from dealership was to carry a device in the car the break out the window in case of accident.