Originally Posted by wayfaringgirl
I was quoting Pooneil -- I assumed he meant converter.
The dealer told me I could pull one of the fuses on the inside to cut the power for storage -- I know I'll forget to do that at some point...
Sorry about the confusion. My posts here were a bit wide ranging because I was also talking about a personal setup that included an inverter to give me 120V AC.
Specifically for your situation. You can move the positive wire from the battery to your camper and install an on/off marine battery switch in the line. That way you can be assured the battery is completely disconnected form the trailer with a glance at the switch. The camper probably uses 10 gauge wire. You should use wire of the same gauge and color of insulation to make your connections.
The mod requires that you have a bit of extra room inside the battery box for the nuts that hold switch or pick another place to mount it. All the wires are outside the battery box. I chose to do this over putting in a fuse because; 1)the circuit is already protected by the breaker, 2) if you remove the fuse and forget it then you have no power, 3) you cannot see the state of the fuse at a glance.
Electrical issues can be the devil to understand. You are right to take the time to understand the problem and proposed solutions before you make any mod.
ETA I previously mentioned cutting the positive wire. That is not necessary just move it to the switch and add a new run from the switch to the battery. The most you will have to do is crimp some connectors on the wire.