As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF FROM PHL, THE AUXILLARY BATTERY TEMPERATURE WENT INTO THE CAUTION RANGE. THE BATTERY REMAINED HOT WITH THE SWITCH IN THE OFF POSITION. INDICATION WAS IN THE MID SCALE AREA WITH NO ASSOCIATED HOT LIGHT. MAINTENANCE REMOVED AND REPLACED THE AUXILLARY BATTERY IAW DHC PROCEDURES. VOLTAGE AND TEMPERATURE CHECKED GOOD. AIRCRAFT RETURNED TO SERVICE. (M)