Voltage Regulator

All was good Sarurday when 35 miles into our ride i notice my volts going downhill. Made the mistake of shutting it off, had to get a jump to get it going. Right after the jump volts was 12 or so. Luckily i was near a road where i could get the trailer too. By the time i shut it down it was 9 volts. Power steering was gone.
At the dealer now ( 900 Trail EPS).
Lucky i did pick up the extended warranty.
Anyone had a similar problem? I am thinking voltage tegulator?
Thanks