I use my lithium house battery to run my breakaway switch. The breakaway system uses no power unless activated and I have the added comfort of knowing that if my house batteries are working my breakaway system will work as well. Keeping the batteries warm will greatly improve their performance. Keeping the batteries cool will extend their life. I put mine inside for better temperature control and it’s also much harder to steal.Helping a friend put solar on his new 16' travel trailer. His came with a single deep cycle lead acid battery on the trailer tongue used for the house power, and wired into the break away switch for the electric brakes. His didn't have a tiny frame battery like my flatbed car hauler has. We plan on replacing it with 2 100ah lithiums in parallel, and we will install a small battery on the frame for the break away electric brakes the trailer brake will trickle charge it. I find my car hauler the battery doesn't last long I just replace it before I use it since it sits most of the time.
We don't want the truck 7 wire charging the lithium batteries. We installed a Victron blue smart charger if he needs to use shore power to charge. We fabricated a nice box for a honda inverter generator in the back of his pickup to secure the generator. Mostly boondocking and camping in cool climates won't need the AC much likely it might only be used for the microwave. He have a small inverter for a small TV, or items needs. I think with 600 watts of solar and 200 AH of lithium power should be more than enough. We did some testing with a single 100 ah cheap $270 LifeP04 I got on eBay for experimenting with solar on a shed in my backyard it was way better than the interstate Deep cycle they gave him. I'm only concerned is about the lithiums being able to handle cold weather in a box on the trailer tongue. He is going with Battle Born they say go down to -4 up to 135F we could go with the heated versions. Maybe we put some insulation in a box up there.