As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING BOARDING, CREW NOTICED AN ELECTRICAL SMELL IN THE CABIN AND INITIATED FAULT ISOLATION PROCEDURES. THE BATTERY CHARGER CIRCUIT BREAKER TRIPPED AND THE MAIN AIRCRAFT BATTERY OVERHEATED. BATTERY AND CHARGER REPLACED. BATTERY HAD NOT BEEN MODIFIED PER BOEING SL.