Yes, we've plugged it into the 12 V outlet, and no, no overheating. I would say that results will probably vary based on your particular electrical configuration, I know there is a lot of variability out there. I don't think it's a high risk to plug it in and give it a try on a half hour drive, or even just idling in the driveway you can monitor your input for a bit and see how it goes. 12 V charging is much slower than charging by solar or AC, but if you are driving anyway, and your camper battery is already charged, might as well charge the jackery, at least that is the way I feel.