As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
MAIN BATTERY SHOWS 27 VOLTS AND 1 AMP CHARGE THROUGHOUT THE FLIGHT. PERFORMED MAIN BATTERY CHARGER OPS TEST REF MM 24 31 21 710 801 OPS TEST GOOD. REPLACED MAIN BATTERY REF MM 24 31 11 000 802 002. BATTERY INSTALLATION TEST & GRD FUNCTIONAL TEST PASSED.