As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING EMERGENCY LIGHTS TEST, FOUND EPSU BATTERY PACK RT MESSAGE. APPLIED TSM 33-51-00-810-802A. PERFORMED OPS TEST OF THE EMERGENCY LIGHT SYS. FAULT CONTINUES. PERFORMED OPS TEST OF THE BATTERY PSEU. BATTERY FAULT APPEARS. R & R BATTERY IAW AMM 33-51. TEST OK.