As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BAT DISCHARGE LIGHT ON. GROUNDED - YES. BOTH BATTERIES, AND MAIN BATT CHARGER REPLACED IAW B737-800 AMM 24-31-11-000-802-002, 24-31-11-400-802-002, 24-31-21-000-802-002, 24-31-21-400-802-002 REV 76 OCT 15 2021. OPS CHECK NORMAL A/C OK FOR SVC.