I've thought about it on more than one occasion. We spend countless hours in our truck, and it would be a LOT easier if I could put the sticks in there and know they were staying prime.
But, it's probably way more work than it's worth. I already run an 1200 watt power inverter in the truck, and that's killed a battery and an alternator. I wouldn't want that on all the time it would need to be, to keep the cigars right. I used one of the portable car coolers years ago, that plug into a cigarette lighter. I accidentally left it on, and ran out to get something from the truck a few hours later. Came out to the plug smoking and melted. I just can't get over that and trust them again.
In the end, I only take my stash with me-when I'll be in the truck with the climate control running. If they will need to sit in there for an extended period, I just take my 3 count with what I need/want for the day. I've had it sit in 100 degree temps, and they sticks were just fine later. Just don't leave your HTF's sitting outside for weeks, and you aren't too much at risk.