As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LOOSE BATTERY CABLES LED TO A COMPLETE LOSS OF ELECTRICAL POWER WHILE IN FLIGHT AT IFR FLIGHT LEVEL 13000. LOOSE CABLES CAUSE A LOSS OF ACFT BATTERY. WHEN THE ALTERNATORS WERE UNABLE TO CARRY THE LOAD, IT RESULTED IN TOTAL ELECTRICAL LOSS.