2001 BMW 325XI Engine Problems

I THINK I KNOW WHY THE CAR CATCHES ON FIRE SINCE MINE ALMOST DID AND I TROUBLESHOOT THE PROBLEM. THE ALTERNATOR IS NOT DISCONNECTED FROM THE BATTERY WHEN THE IGNITION KEY IS TURNED OFF AND THE CAR IS PARKED IN THE DRIVEWAY. IF THE ALTERNATOR EVER OVERHEATS FOR ANY REASON (SUCH AS THE COOLING VENT COMES LOOSE), THE PASS TRANSISTOR IN THE BUILT IN REGULATOR OF THE ALTERNATOR BEGINS TO SHORT. SINCE IT IS NEVER DISCONNECTED FROM THE BATTERY (EVEN WITH THE IGNITION KEY REMOVED) THE FIST SYMPTOM APPEARS TO BE A BAD BATTERY AS THE ALTERNATOR KILLS THE BATTERY. ESPECIALLY IF YOU REPLACE THE BATTERY WITH A NEW, FRESH ONE AND CONTINUE TO DRIVE THE CAR THE PASS TRANSISTOR CONTINUES TO SHORT MORE AND MORE (IT CHARGES THE BATTERY MORE AND MORE LEADING TO OVERCHARGING AND POSSIBLE FIRE) AND EVENTUALLY SHORTS SO BAD THAT EVEN WHEN TURNED OFF IT...