As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON CLIMBOUT FROM KPDK, NR 2 OVERHEAT LIGHT CAME ON. ALTITUDE WAS FL330, RAN BATTERY OVERHEAT CHECKLIST. BATTERY NR 2 TEMP CONTINUED TO CLIMB. DECLARED AN EMERGENCY AND RETURNED TO KPDK. BATTERY TEMP ON NR 2 BATTERY HELD AT 81 DEGREES CELSIUS UNTIL LANDING. MAINTENANCE FOUND ONE CELL IN NR 2 BATTERY SHORTED.