Dan B

I am interested in doing something similar but I have a complicated problem. My current situation is like the schematic below. The reason for this is that my house is 2 stories tall. The solar is on the roof along with the outdoor end of the aircon. The house is brick so we can't just run new cables. Even adding outdoor conduits is nearly impossible because the main breaker panel is in the center of the bottom floor. So with this setup, the same cables used to power the aircon are used to bring the power generated from the solar down to the main breaker and out to the grid (if there's excess). The problem is that when the main goes out, we have no power at all. It looks like in the systems you all have posted here, you are still able to put the inverter between the grid and the main breaker panel, but that is not an option for me. I was thinking of doing some sort of auto switch where when the main goes out, a switch at point B would automatically disconnect the main. Then a new hybrid inverter (replacing the old) would switch with an automatic switch at point B. That would disconnect the house wiring from the main inverter output to the UPS or EPS output. I like the idea of wiring a light as an alarm to know when this happens. The only problem I can see with this is that when the main comes back, I couldn't switch B back to the grid until A is first switched back to grid side of the inverter. But I'm thinking a small signal cable or two could fit in the existing conduit to make the switches work in the correct order. I am a little worried that the main breaker is in a brick wall and it wouldn't be too easy to put a switch between the main and the rails in the box, but i'm sure i can find an electrician with some ideas. Is this possible? Am i missing something? A little extra background: I live in the middle of the jungle and the power grid isn't too reliable. My wife and I work during the day from this house with various computers and equipment. Right now we have our network on a big UPS that will work for a few days but our computers and screens won't. We want those to run on the solar if the grid goes out, with maybe just a couple batteries, not enough to run the whole house on for a long time. We only need it during the day, and it's usually sunny. The power goes out frequently but not usually for more than just a day or two. The computers are all too far apart to put on their own UPS circuit, so we would rather just power the whole house and turn off our aircons if we need to. We also have an underground cistern with a water pump, so without power we also have no water. My current setup diagram: