As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT AUX BATTERY INDICATED +2 AMP CHARGE CONTINOUSLY FOR 2.5 HOURS. VOLTS WERE STEADY AT 27. MAIN BATTERY INDICATED 27 VOLTS 0 AMPS FOR ENTIRE TIME. NO OTHER ELECTRICAL SYSTEM ABNORMALITIES NOTED. REMOVED AND INSTALLED MAIN AND AUX BATTERY REF 24-31-11. PERFORMED OPS CK PER SAME STEP I. SYS CHECKED NORMAL.