As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING EMERGENCY LIGHT TEST AMM 33-51-00-710-001-A FAULT EPSU BATTERY AFT L WAS RECORDED. USING TSM 33-51-00-810-802-A VERIFIED AFT L BATTERY OF EPSU 13WL IS AT FAULT. VEREFIED BATTERY REPLACEMENT AND OPS CHECK GOOD REMOVED AND REPLACED BATTERY OF THE EMERGENCY POWER SUPPLY UNIT (EPSU) AFT LH 13WL IN REF TO AMM 33-51-38-400-002-A. OPS CHECK GOOD. SDR#1031976 SUBMITTED.