I run mine on 12 volts w/o harm so far but your right, it blows like a hurricane. Too fast even at the low setting. I'm using a rheostat switch from NAPA. You can put shunt in the line, at least that works for gauges so why not for a motor? The 12V-DC power will really spin the starter too but seemingly has no ill effect if you don't grind on it long and overheat it.
I suggest the Picturetrail site for photos but lots of good free one available.
