As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTS MAIN BATTERY AND MAIN BATTERY CHARGER EICAS MESSAGE ON TAXI OUT. BATT VOLTS 26VDC, 0 TO 1 AMP CHARGE INDICATED ON MX PAGE. NEED TO ACP TEST OF MAIN BATTERY & MAIN BATTERY CHARGER SYS BEFORE DEPARTURE. REPLACED BATTERY & MAIN BATTERY CHARGER. ALL INDICATIONS CK'D OK.