And on a side note about charging with your car battery...
I developed a little problem with my onboard charger power plug bouncing out of it's socket. I thought I had battery problems until I snooped and found the problem.
While in Southern Oregon on my last rek, I forgot to check and I guess for two days, even tho I was plugged into AC, I wasn't charging the battery. Hardly noticable on a full charge and running most everything straight off AC anyway. In my experience with my rig, two days goes well. After that, it drops into oblivion pretty quickly. The only charge it was getting was while I drove, and with the fridge
running on 12v, it was not much of one.
The ONE nite I spent with no hook ups and had to use my on board propane
heater was the next stop. By the morning, the battery had sufficiently been used to the point of worry. And no way to charge, my solar panel
would have been useless. (I left my generator
at home, knowing I would be hooked up 99% of the time.)
I hooked up the car pigtail and let the car run for 1/2 hour or so. It managed to get the battery back up enough to do my dishes and have lights
and heat for my morning coffee and prep. I also ran my TV off a small handheld invertor and my extra gel cells. (This is EXACTLY why I put those in, for emergencies like this) and was able to get the weather news during that big storm.
It is nice to know I have yet ANOTHER back up option for future disasters, and this one doesn't require any extra set up or hassle.
A charge line wasn't that big a deal to me, I just had it done when my brake controller was done because they were in there anyway. Glad I did!