What was found
AIRCRAFT STILL POWERED UP AFTER BATTERY IS SELECTED OFF. BATTERY BUSS TIE CONTROL T/S. FOUND THAT BATTERY RELAY WELDED CLOSED. REPLACED BATTERY RELAY. BATTERY BUSS TIE RELAY INSPECTED AND FOUND CONTACTS BADLY PITTED. REPLACED BATTERY BUSS TIE RELAY. OPS CHECK CARRIED OUT AND FAULT STILL RE-OCCURRED. METERED OUT SYSTEM AND FOUND THAT BATTERY FEEDER DIODES SHORTED. REPLACED DIODES AND SYSTEM CHECKED OK. BUS CONFORMITY CHECK AND TRIPLE FED BUS SYSTEM CHECK CARRIES OUT. CHECKING SERVICEABLE. WOULD SUGGEST THAT AT A REGULAR INTERVAL THAT THE RELAYS AND DIODES BE METERED OUT. RESISTANCE VALUES WOULD DETERMINE IF THE RELAYS ARE GETTING WEAK AND WOULD ALSO TELL YOU IF THE DIODES ARE STILL WORKING.