As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE BASE VISIT AFTER CLEANING THE AIRCRAFT THE GROUND CREW NOTICED HALF THE EMERGENCY LIGHTS ILLUMINATED UNCOMMANDED. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED THE NR 4 BATTERY IAW EMB140 AMM 33-50-04. THE OPERATIONAL CHECK WAS GOOD, NO MORE DEFECTS NOTED AT THIS TIME. THE AIRCRAFT WAS RETURNED TO SERVICE.