In principle, this works. However, you need a shelly pro 3em or Zendure 3ct which is installed in the fuse box. However, if you already have batteries, I wonder what added value you are expecting. Depending on how they are controlled, it can happen that the batteries just keep trying to equalise. You can use the Hyper with or without solar panels.

Sorry, it didn't take over the whole text

The question would be: I need a zero feed and already have solar panels and batteries in use. So I am looking for a battery without solar panel ac decoupled that absorbs the surplus. Is this possible with Hyper 2000