As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING CLIMB OUT FROM YWK, THE CREW RECEIVED A "MAIN BAT HOT" RED WARNING MSG ASSOCIATED WITH A HIGH TEMPERATURE ON THE BATTERY TEMPERATURE MONITOR. THE ACFT RETURNED AND LANDED WITHOUT FURTHER INCIDENT. MX CONFIRMED THE BATTERY SUFFERED FROM A THERMAL RUN-AWAY. THE MAIN BATTERY WAS REPLACED AND THE ACFT RETURNED INTO SERVICE. THE BATTERY TEMPERATURE WAS NOT RECORDED.