As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BATTERY TEMPERATURE ROSE TO AN OVERHEAT CONDITION WITHIN 30 MINUTES AFTER DEPARTURE. CORRECTIVE PROCEDURE ISOLATED BATTERY FROM GENERATOR CONTINUING TO HEAT BATTERY. BATTERY EXAMINED BY MAINTENANCE TECH AND DISCOVERED TO HAVE BAD CELLS. BAD BATTERY REPLACED WITH NEW ONE.