Heated full face visor power Q...

Ok, so I normally run a full face helmet, I wear glasses, I can get my glasses not to fog, but my visor does...

Now I can get a heated visor for about $100 ish... but I have to wire it to the sled.. which is an issue, because I don't always ride the same sled, and sometimes switch mid-ride.

Being I mainly ride with my wife, and her being a novice(only has riden twice) I don't want to be tied to my sled in any way...

Does anybody know how much juice these thing pull? How practical would a custom made battery belt be? prolly use rechargables, prolly NiCad, not litium Ion or Nickel Metal Hydrate just due to cost.

Or would switching to googles with a percription insert be better?

Thanks

My idea, was maybe a couple banks of 8 D cell batteries.. so 8 in series to make 12V, then maybe 2 or 3 banks or make it last longer Plus 8 D cells are easier to shove in a pocket, or make belt from than one larger UPS type battery. I mainly trail ride, so I don't have a back pack... I normally stay within 3hr walking distance of my car or home, just carry a cell for worst case situations.... but I could get a small pack...

Just thinking of which would be the better solution... both will cost about the same.. by the time I get the battery and visor and pack.. or the googles..

The difference would be the googles I'd have to wait for, the visor... and such I could pick up on the weekend... but I don't want to waste money on one solution when another for the same price is better.

Thanks for the idea though...

***EDIT*** just looked that battery you posted is only a couple lbs.. and like 6" long,. by 3" by 3" I was expecting bigger and heavier... that thing would almost fit in a pocket of my parka... or a leg pocket of my bib... How long did your visor last on battery? and how warm did it get? just warm enough to keep the visor fog free, or a little warmer than that?

heh contacts... if I could stand touching my eyes... sure.. my wife just got a bunch of disposables for sledding... but me.. hmmm