As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED DEFECT AND MAINTENANCE CORRECTIVE ACTION: ON 3RD HOP, 2 MINUTES INTO FLIGHT VOLTMETER READ 23 VOLTS. NO GENERATOR LIGHT. SHUT DOWN FOR 10 MINUTES. CONTINUED FLIGHT FOR 3 HOURS. AT 29 VOLTS ON 4TH HOP, JUST PRIOR TO LIFT-OFF, GENERATOR LIGHT CAME ON AND WOULD NOT RE-SET. REPLACED STARTER/GENERATOR AND BATTERY.