As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTS A LOW VOLTAGE INDICATOR WARNING CAME ON WHEN HE WAS IFR IN IMC CONDITIONS WITH A HEAVY ELECTRICAL LOAD. FOUND BOTH ALTERNATOR BELTS WERE SLIPPING AT HIGH ENGINE RPM AND HIGH LOADS. TIGHTENED BOTH ALT BELTS. RECOMMEND ALTERNATOR BELTS BE SERVICED PER MM. NOTE: BOTH BELTS HAD APPROXIMATELY 150 HOURS IN SERVICE SINCE NEW.