As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
JFK - EEL - DURING 8-DAY CHECK THE LT OVERWING EMERGENCY LIGHT POWER SUPPLY BATTERY FAILED DURING EMERGENCY LIGHT TEST. MAINTENANCE REMOVED AND REPLACED EMERGENCY LIGHT BATTERY PACK AT LT OVERWING EMERGENCY POWER SUPPLY UNIT (11WL), OPERATIONAL CHECK WAS GOOD.