I’m trying to understand the feasibility of setting up a pair of MultiPlus-II 2.x120 (12v) in a motorhome that has 50A service. The install would be between the transfer switch and the main breaker panel. The specific thing I’m trying to address is how I might shed loads in the situation where power is lost while many high loads are on and these loads need to be shed before the inverter starts drawing power from the battery. Note that this is not a new install but a retrofit - so trying to minimize big changes and complicated wire pulls…
I have a 30A/240 line that goes from the inverter to the main panel. The idea is to repurpose this line to be a “signal” line (l1) to a bank of normally open contactors. When power is lost, the contactors will open.
It’s really a simplification. This is in an RV. I already have a pair of 10/3 wire that goes from the inverter to main panel. But the inverter is at the front and the panel is at the rear. Running a new 6/3 wire from inverter to main panel will be very difficult. So rather than run new wire, the idea is to use the existing 10/3 wire to act as a “signal” to a relay bank. There is room for a relay bank box.
I can make it a good distance under the RV in the frame rails with conduit. That’s the easy part. But then I need to get past the rear suspension and engine. From what I can tell they run the wiring harness in some difficult to get to location, maybe somehow above the rear tires and below the floor. But there’s no access there that I’ve found yet. I’ll investigate some more, but at least now I have workable solution based on the existing wiring to the main panel.
Yes a Cerbo will be in the mix. I don’t think any wireless or logic based solution will work. It would have to be hard wired. The “non essential” loads would need to be turned of in milliseconds - before the inverter tries to supply power to those loads in a power outage.
