It is possible that the TS was a bit overwhelmed by the discussion. Some of it got rat er technical and complex.

Since he hasn't been on this website since Dec. 27, I don't think that's the problem.

 

The TS seems to have left the building.

Hello @crutschow

I haven't been able to access the forum since January as I had issues with my phone. Feels good to be back here.

 

This is SO easy and everyone is making it SO hard.
Buy an ATS (automatic transfer switch).

Step one - put the ATS into "manual" mode.
Step two - move the ATS switch to the inverter input side.
Step three - put the ATS into "automatic " mode
Step four - after the grid returns the ATS will automatically switch to the grid.
Step four - go to step one.

Buy the ATS - unless you are a die-hard DIY person and think you can somehow make one as safe and reliable as a commercial device that's been around forever. Amazon might have the best selection. The size you need costs maybe 40 bucks.

Dont
Don't bother (unless you like reinventing the wheel). Just buy an ATS -Automatic Transfer Switch - off Amazon - about $40. Boats and home systems use these all the time (including me). Priority is grid or inverter. Switches back when lost power comes back on.
I like this one...I use it when charging my car. Get it for any configuration - 2 pole, 3 pole, etc.

I like this one...

I know what an ATS is and how it works.

You seem to not understand what is needed here. ATS wouldn't work with the task here.

 

In some parts of the world those handy automatic packages are not available, or way too expensive, and from another friend in still another part of the world, (almost as far away as possible.) a lot of stuff is rather poor quality.
AND the TS mayjust be wanting to build it themself.