As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ACFT WAS NOT OUT OF SERVICE DUE TO THIS EVENT REFERENCE LP275822 ITEM NR 3. DURING HEAVY CHECK EPSU BATTERY 10WL FWD L, FAILED TEST. AIRCRAFT REMOVED FROM SERVICE. REMOVED AND REPLACED THE EPSU BATTERY 10WL, FWD LT IAW AMM 33-51-38-000-002-A/400-002-A OPS CHECK GOOD.