I was charging stuff off my truck a few years ago, and at one point was not paying attention and had the heater turned on in the truck while I had the key on but motor off. A panic situation developed when my truck was dead in an out of the way spot, but I got lucky and was able to round up a jump. Still, it spooked me and I have been taking a spare 12V battery with me in my truck on my trips by myself to remote places, especially when out of cell range. Driving around with a spare wet batt