As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS NOT GROUNDED: DURING OPERATIONAL TEST OF EMERGENCY LIGHTS, MAINTENANCE FOUND EMERGENCY POWER SUPPLY UNIT 10WL BATTERY CHARGE LOW. MAINTENANCE REPLACED THE EMERGENCY POWER SUPPLY UNIT 10WL BATTERY PER AMM 33-51-38. A SATISFACTORY OPERATIONAL CHECK WAS ACCOMPLISHED.