As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING INSPECTION THE NR 4 EMERGENCY LIGHT BATTERY PACK WAS FOUND TO BE INOP. MAINTENANCE REPLACED THE NR 4 BATTERY PACK, BUT AFTER INSTALLATION OF THE NEW BATTERY PACK, THE OVERWING EMERGENCY LIGHTS WERE STILL INOP. THE BATTERY WAS REPLACED AGAIN WITH NO FURTHER DEFECTS NOTED.