Hi all. Newbie here. I have a 721 air cooled diesel with the Duetz in it. I put a vinyl cab enclosure on it for winter. It is a great wind blocker. But, still cold in these Minnesota winters. I use a propane heater to warm it up good before using it. However, no available heat inside. Has anyone found a 12v electric heater that works fairly well on these? I am not looking to move snow in shorts and a t shirt. But something to keep the windows somewhat defrosted would be nice . Thanks