The max power you can draw from a cigar lighter is 120 watts .. which can heat 0.5 litres of water by maybe 0.06 degrees C in a second. That kettle takes 1120 seconds to go from 20 to 100 C... The max power you can get from the alternator is about 600 watts. Which will drag about 2HP off the engine .. Meanwhile out the back of the car is a 10-50 kilowatt heat source. Even the repro heat exchangers manage to gather more than 150 watts ...
Ok. I've ordered one of those in- cup elements and I'm going to do a Trevor Bayliss in my garage.....
