As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING MAINTENANCE INSPECTION FOUND THE BATTERY VOLTAGE PROPS RAPIDLY BELOW 23.5 VOLTS AS SOON AS GENERATOR POWER IS SHUTDOWN. THE AIRCRAFT WAS REMOVED FROM SERVICE. REMOVED AND REPLACED BATTERY 1 AND 2 IAW WC 24-600-00. THE OPERATIONAL CHECK WAS GOOD. THE AIRCRAFT WAS RETURNED TO SERVICE.