sorry to make you write the artical but I'm sure some will get a lot out of it.
Thats what I do now as I have a 2nd battery loop. I have a smart switch the fails open as a safety precaution. only when the crack has 12.7v or more will it close allowing the second battery to charge. Same idea different brand. My idea is though, as it has a anderson plug arrangement, is to remove the 2nd battery from the jeep at night and attach to the camper for the fridge and lights. In the morning stick it back in the car and replug to JK. Plug the orignal camper battery back in and along with the solar panel the fridge can run all day with very little power loss as the solar will add between 3 and 5 amps. The second battery in the jeep can recharge whilst we are out and about.
one like this in the back of the JK (getting a new box as the old one doesn't fit a 110amp battery)
