I’ve been thinking about doing this with a Jackery.
Here is my thot process.
1. Have a break away battery on tongue hooked up exclusively to trailer brakes. Here is the e trailer link for the battery I am thinking.
https://www.etrailer.com/p-HM20008.h...ils=.questions
1a. I do have a battery tender that I use with my current lead acid batteries. That I would hook up in between trips to the trailer brake battery and hook up the trailer brake battery to the 7 pin to charge it while towing.
2. Jackeries do have a 12 volt 10 amp output. Hook this into the twelve volt system running wire to the back locked compartment.
3 Put in some vents in compartment just in case.
4. This way I can use the jackery for other things than camping in the TM.
Any body see any potential problems with this set up.