As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EMERGENCY LIGHTING SYS BATTERY POWER SUPPLIES DRAINED. REPLACED ALL FOUR EPSU BATTERY PACKS IAW MM 33-51-17. OPERATIONS TESTED GOOD. OPERATIONAL CHECKS BALANCING ITEMS 3 & 4 ON LOG PAGE 3754114 WERE ACCOMPLISHED SUBSEQUENT TO EPSU PACKS REPLACEMENT. EMER LIGHTING BATTERY PN 2013-1A NR 2 SN 105211 NR 3 SN 103166 NR 4 SN 83285.