I have four hot wires on my setup.
As you can see in the photo, one red wire is from the battery, from and to the converter and to the breakaway brake switch. This circuit goes through a 30A inline fuse; just outside of the photo.
The other red wires are labeled and are the positive to the power winch (with a circuit breaker right at the battery), and the other one goes to the second battery positive cable. The thin black wire is the Trimetric Meter I installed inside the trailer.
It appears when looking under the trailer, the TV hot wire, converter hot wire, battery positive wire and breakaway brake wire are all spliced together.
So when the TV is connected, power is supplied from the TV to the battery and to the converter. The converter will use it for the detectors and for the fridge if switched to the 12 volt mode.
When the TV is disconnected, the battery will supply the 12 volts to the converter to use for whatever is required in the 12 volt circuits of the trailer.
If the trailer disengages from the TV, and the brake breakaway pin is pulled, the batteries supply 12 volts through the switch out to the brakes to, hopefully, stop the trailer.