Well if you figure it out post it. And I will run it in my house.
Free heat sounds good to me.

Spare deep cycle battery and a space heater sounds like the best bet.

 

Resistive loads like a heater are the absolute worst for running off a battery. The reason is that they don't only draw a lot, but the load does tout decrease. If you start a motor for instance, you have a high current draw, but it tapers off after the load starts.

I have a fair amount of experience with high load dc systems on boats. You will need a very large battery bank if you want to run even a small space heater overnight. If you had 2 8d batteries you could pull it off.. But you would have to sleep in the front seat since you would not have much room in back.

Simple? How about one of those propane heaters (catalytic) like the "heater buddy"?

More complicated? Installed bus heater, like a walbougough unit. They make cool ones that run off propane, or deisel.

On edit: mr. Heater, less then $90 at walmart.
http://www.walmart.com/ip/14710768?...000000000&wl0=&wl1=g&wl2=t&wl3=21486607510&wl4=&wl5=pla&wl6=19880599990&veh=sem

 

Good Grief!! I feel REALLY stupid...

They say that the simplest answer is usually the correct one...and I hadn't even thought about using a Buddy Heater. I only have about 3 of them that I use in my deer blinds during hunting season.
:banghead: :banghead: :banghead: :banghead: :banghead:
Thanks for the suggestion. That will work out perfectly, just gotta keep a window craked a little.

 

http://www.atomicheater.com/

I wonder if this really works, if so it could certainly be made by an average DIY'er

 

It looks like it vents some of the fumes, but I would still have a window open, just to be safe

 

If you click on the link to the site you'll see the unit has a lid that latches on, essentially sealing the fumes into it's exhaust system. Seems like it would make sense to weld on heat sinks to actually capture the heat instead of blowing it all outside

 

If you were so inclined, you could install an RV/Marine style heater. Then you wouldn't get all the added moisture inside like you get from the catalytic heaters. But as far as cost goes, you can't beat those little propane heaters.