As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BATTERY INDICATES 14 VOLTS -11 VOLTS. AUX BATTERY INDICATES 14 VOLTS - 12 VOLTS. ACFT GROUNDED. REPLACED MAIN BATTERY REF MM 24-31-11, OPS CK OK. R & R AUX BATTERY REF MM 24-31-11. OPS NORMAL IAW SAME. ETOPS GROUND VERIFICATION TEST SUCCESSFUL.