On Sunday, I was able to bring the solar panel wires all the way in to where the solar controller is. In this photograph, they come in on the upper left, go through the upper switch, and then into the solar controller. I’ve also added a fuse for the solar controller which is in front of the larger fuse for the inverter.

Here’s the modified faceplate I showed in a previous post, now with the new thermostat mounted and wired up for testing:

Seems to work really well.  I now need to add a second thermostat, as Trish likes her water a bit hotter than the rest of us.  There will also be a switch that will be used to select which thermostat to use.

I mounted the three new solar panels on the roof a couple months ago.  Now that the controller is installed, I ran the wires from the back of the RV where the three new panels are installed, skirting the original panel at the front of the RV to get to where the controller is installed.  I used various tools to hold down the wires while the caulk dried:

I ran the wires from the roof down into a cabinet, now I need to get them to the controller.