The biggest problem that I have personally found is the complete lack of ability for an electric unit (which are typically small) to get the windshield clear, let alone keep it clear.
Most of the systems I have researched were around electric vehicles, as the cigarette lighter types werent a reasonable option. The electric car units are running on very high voltages that a gasoline engine cant typically produce. That, and they are prohibitively expensive to engineer in to the car.
You can ask anyone on here, I am a research freak. *thumbs up* Even after being told " No it cant be done" I still try to find a usable option. Probably even irritatingly so. *na-na-na* Sry, just my nature.
I am not saying some new tech may not be out there, Only sharing what I have personally found thus far.
The best option for myself was to just use the given heat from my liquid cooled setup.
You can check out this thread:
http://www.sterlingkitcars.com/memb...ve-thought-heat-exchangers-electric-heat.html
In it I "might have" come up with an Aircooled powered version of the typical liquid cooled heater.
its a simple water/oil heat exchange unit, by frankenstiening parts together to achieve the same effect as a modern car. In theory it should work quite well.
Yaughn