I think going forward this will be a very popular question: How to combine/integrate a Wallbox-Charger in/with an ESS System? What I'm not looking for are answers like: use the internal relay of a MultiPlus to turn on the charger when the ESS Battery is full.
It should be a smart integration in which the user can dynamically set the priorities, like:
1. charge the e-car using the remaining PV-power (ESS battery has 1. priority)
2. charge the e-car using all available PV-power (ESS battery has last priority)
3. charge the e-car as fast as possible
Options 1 and 2 would mean that the charging performance is constantly changing.
Possible solution: use an external control unit which communicates with ESS and the Wallbox via Modbus. A control unit could be an OpenHAB system. I'm using such a system successfully for my smart home... A programmable Wallbox could be KEBA P30 x-Series.
The idea is to write a simple script which constantly reads some ESS figures, calculates the remaining power and sets charging power within the Wallbox. Option 1 could be realized quite easy, I guess. Any objections? Option 2 is more complex, but I think it could be solved as well. Option 3 is done without involving the ESS.
Now, the big questions are: has anybody out there done this task already and can share the solution? if not, what other ideas do you have to solve the above challenge?
Many thanks in advance!