As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PERFORM DEEP-CYCLE EMERGENCY LIGHT BATTERY PACK CAPACITY CHECK F OUND BATTERY M33096 POOR CAPACITY REF HAECO NON-ROUTINE NO.: 944 4852, ORIGINATED BY EMP V905497, SPEC NO.: B777-33-3-7019. PERFORMED BY EMP V903172, REPLACED EMERGENCY LIGHT BATTERY M3309 6 AND CARRIED OUT OPERATIONAL TEST FOUND NORMAL AS PER AMM 33-51 -06-960-802 REV 92.IDT BY TA591.