My sisters are motorcycle riders...and I mean HARDCORE
they ride in COLD weather.
they had heated clothing which was powered by the motorcycle battery.
Preeeeety good idea. I could have used something similar when I was delivering newspapers in the early morning cold from MY motorcycle...back in the day...
Nowadays you can buy dual-mode heated clothing that will run off a motorcycle 12v socket or an included battery. I've recently ordered some pants that work that way. Best of both worlds, if they turn out to be any good.
hmmmm...I wonder how it work in a kayak?