Interesting problem

[kb0zke]

Earlier this year we installed a fairly robust solar system (three 365W panels, two 24V 200AH LiFePO4 batteries, and a MultiPlus II). We've "boondocked" a few times by simply turning the shore power off to see how things go. This morning we were going about our normal activities when I went out to fill and dump. When I opened the door to turn the handles and hook up the hose I noticed that there was no shore power. I flipped the breaker a couple of times, but no change. I told Jo Ann we were operating on batteries. A few minutes later I found out that the entire park was without electricity. Not more than a minute after that the power came back on.

Part of the reason for our upgraded system was just for times like that, but I realized that there is something missing. Suppose this was in July and both air conditioners were going. I'm guessing that the main fuse on the low voltage side would blow because there would be too much current being drawn. I wonder if there is something that can be added to the system that would cut the power to one of the air conditioners and alert us to the fact that we suddenly are on batteries.

When thunderstorms are predicted it will be nice to be able to unplug from shore power and stow the cord before the storm hits, but when that happens I can turn off one or both air conditioners. This was a complete surprise.

[durangodon]

When I had a generator installed for my house, they offered to install a certain type of breaker which would automatically kill that circuit if power went out and I went to generator.  I could have put one on the water heater or a/c, but did not because my whole house generator could handle everything.

I don't remember what they called it, but I don't see why it would not work in your situation also.  Maybe someone else knows what they are called.

[Wrknrvr]

What kind of A/C units do you have. And what thermostat do you have.

 

  With that information, things may be able to figure your situation out.

[BamaDuke]

Is your inverter tied directly into the same panel as the shore power?  Is it 30A or 50A?  If 50A, one of the ACs is typically tied to one side of the 50, and the other AC (as well as the rest of the RV) is tied to the other leg.  If your inverter setup is tied to only one "leg" of the incoming shore power, you already have the problem solved.

BamaDuke

KC5NCZ

[Chad Heiser]

With a Multiplus inverter charger installed in a “whole house” setup it is simple.  By whole house set up, I mean the inverter powers all circuits in the RV.  Simply set the Multiplus to Charger Only instead of On when you are plugged into shore power (30 amp or 50 amp pedestals) where power assist isn’t needed.  Charger Only will pass the shore power through and keep the batteries charged, but it won’t invert if the shore power goes away.  This way, you will know the power at the pedestal was lost and you can take the appropriate action.  In other words turn the inverter on and manage loads accordingly until shore power is restored.