As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING FLIGHT, THE CREW NOTED THE BATTERY WAS NOT CHARGING SINCE THE BATTERY CHANGE LIGHT HAD STAYED ON SINCE START UP AND WAS STILL DRAWING 10-20 AMPS. INSTEAD STRANDING THE AC, THE DECISION WAS MADE TO PERFORMED AN AIR-TURN-BACK. MX CHARGED THE BATTERY AND INSPECTED THE SYSTEM AND FOUND NO DISCREPANCIES. MX REPLACED THE BATTERY AND RETURNED AC TO SERVICE WITH NO FURTHER DEFECTS. (K)