I ended up installing the shunt in the battery box. The low voltage design of this trailer is horrible.
Anyone notice the flaw in wiring? Amazingly this is how it was wired from the factory. The 6ga cable is horribly undersized and results in battery voltage of 13.2@45A during boost mode charging (~14.2v output from converter).
The flaw is there are connections to the positive wire between the battery and the cutoff switch. I am hoping the orange wire is for the break away switch but I am still getting +12 at the converter output wires even with the converter power off and the battery switch off so its feeding back at some point. Terrible and dangerous design!
I am going to start looking into replacing the 6gauge thhn cable with some high quality 2ga welding cable. At least between the converter and the battery. And possibly some 4ga between the converter and the RF switching box (not sure what to call it, it allows the jacks and slides to work on remote control).