What was found
AFTER START RECALL FOUND ELECTRIC LIGHT ON. RAN QRH AND RETURNED TO GATE. ACFT GROUNDED. PERFORMED FIM TASK 24-31, TASK 801. FOUND BATTERY CHARGER "INOP 1" MSG. PERFORMED FIM TASK 24-31, TASK 804, FAULT MSG CLEARED. PERFORMED MAIN BATTERY, OPS TEST 24-31-21-710-801, TEST PASSED. NO ELECTRIC LIGHT, FAULTS, GROUND VERIFICATION SUCCESSFUL. REPLACED MAIN AND AUXILIARY BATTERIES IAW AMM 24-31-11-000-802-002 AND 24-31-11-400-802-002. REPLACED MAIN BATTERY CHARGER IAW AMM 24-31-21/401 AND ACCOMPLISHED MAIN AND AUXILIARY BATTERY OPS TESTS IAW AMM 24-31-21-710-801 AND 24-31-31-710-801.