As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) THE BATTERY ASSEMBLY FOR NR 4 EMERGENCY LIGHTING POWER SUPPLY WAS REMOVED FOR BENCH CHECK. THE ASSEMBLY WAS INSPECTED AND FOUND THAT THE CELL TABS HAD BEEN OVERHEATED, INSULATION HAD BEEN MELTED OFF AND THE PLASTIC ENCLOSURE WAS ALSO DAMAGED. AN OPERATIONAL CHECK OF THE EMERGENCY LIGHTING SYSTEM & POWER SUPPLIES WAS CARRIED OUT AND FOUND SERVICEABLE.