As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED. JFK, AIR INTERRUPT, JKF-BHX. EMERGENCY DECLARED. LANDING UNEVENTFUL. AIRCRAFT OVERWEIGHT. DURING FLIGHT AND EICAS MAIN BATTERY CHARGER MESSAGE WAS GENERATED. STANDBY POWER SWITCH WAS CYCLED TO BATTERY THEN BACK TO AUTO TWICE. MESSAGE DID NOT CLEAR. REMOVED AND REPLACED MAIN BATTERY CHARGER IAW AMM 24-31-02. OPERATIONAL TEST NORMAL IAW AMM 24-31-01.