As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FOLLOWING PILOT REPORT OF LOSS OF ELECTRICAL POWER, FOUND AIRCRAFT BATTERY WITH 21.9 VOLTS. RG355 BATTERY SUBSEQUENTLY TESTED FOLLOWING CHARGE AT 129% CAPACITY. BATTERY TOTAL TIME 4 MONTHS & 400 HOURS. REPLACED STARTER GENERATOR FOR BENCH TESTING. NO DISCREPANCIES NOTED ON ELECTRICAL SYSTEM. STARTER GENERATOR HAD NO SIGNS OF HEAT OR DUST OR SMELL AND ROTATED SMOOTHLY. TEST RESULTS PENDING.