120V to 12V adapters are fairly easy to come by, but as I recall the connexx uses an odd power cord connector? I had a Connexx, but it broke and I replaced with a Furrion that has a cigarette lighter plug. That said, neither is designed to be taken off - You should have gotten a mounting plate, and the expectation is that you will get another TV to mount for the outside, one that uses 120V.
2022 Jay Feather Micro 166FBS
2019 F150 SuperCrew Short Bed 2.7L
Andersen WDH, 1000 lb Sumo Springs
Past: 2015 Winnebago View, 2004 Blue Bird M380, 1990 Blue Bird WB40, 2003 Safari Zanzibar, 1998 Safari Sahara