As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PERFORM DEEP CYCLE BATTERY PACK CAPACITY CHECK FOUND BATTERY M33407 AT L4 DOOR POOR CAPACITY,REF HAECO NON-ROUTINE NO. 9434143 ORIGINATED BY EMP V905449,SPEC NO.B777-33-3-7019. PERFORMED BY EMP V903258,REPLACED THE CABIN L4 DOOR AREA EMERGENCY LT BATTERY M33407 AND OP TEST CARRIED OUT FOUND NORMAL AS PER AMM 33-51-06-960-802 REV.91.