Hello !
Using 3 Victron Quattro 8000 (three phase configuration) + CerboGx + 16kwt solar panels + 30kwt polyntech
Electricity is not exported (no possibility).
I use it only for my own consumption.
Discovered NodeRed :). But I do not understand it yet 
Help to describe the following task in NodeRed: I want to activate electric boiler connected to CerboGX relay on a sunny day
If the weather forecast for my location is “sunny” and the batteries are fully (>90%) charged - activate the relay on the CerboGX
After that, monitor the capacity of the batteries. As soon as the battery capacity “drops” to 80% - deactivate the relay on the CerboGX
Thank you !