Back when I had the "older" 12 C PolyQuests 2600, I used to heat them (on colder days) on the dash with my car heating on full power. Once I forgot and they were almost too hot to hold in hand [X(]. Not sure if I have harmed them in any way, but the power was great. So how about to pre-heat them in the car and put them into some thermally insulated container, like a small portable cooler?