As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE FLIGHT CREW REPORTED THAT THE LEFT BATTERY WOULD NOT COME ONLINE AFTER DEPRESSING THE BATTERY SWITCH MULTIPLE TIMES FAST. THE MAINTENANCE PROVIDER DETERMINED THE LEFT BATTERY SWITCH WAS DEFECTIVE AND REPLACED IT WITH A NEW SWITCH. OPS CHECKS WERE SATISFACTORY. THE AIRCRAFT WAS RETURNED TO SERVICE.