Consumption optimization of the solar power - SG-ready board necessary?

Hej folks,
in my future home I will heat and prepare hot water with a Stiebel Eltron. Among other things, electricity will be provided by my E3/DC home power plant.
Is there a possibility of consumption optimization in OH without an additional SG-ready board in the inverter? For example, I would like to implement an automation that when there is a lot of solar radiation explicitly the hot water tank is heated or the cooling starts.
Is there another way to address the Stiebel Eltron or is it mandatory to use the ISG web from Stiebel?

Please note that this forum is not on general Home Automation but openHAB related questions only.

Hello Markus, thank you very much for your answer. I assumed that my question was openHAB related.
I can realise a general home automation with the SG-Ready board and other components for a lot of money.
However, I would like to know if it is basically possible to define rules in OH, for example, where I should give priority to charging my battery or heating my domestic water or cooling when there is a lot of sunshine.
It seems that the heat pump and the inverter/battery communicate via MODBUS and I’m a little worried that the devices don’t “understand” the commands.

SG ready is a two-bit electrical I/O signal only. No Modbus or other protocol spoken.
So you can attach any 2 channel OH-controlled actuator to your pump.
Of course you can freely program everything.

Please pay more attention at getting your posts right. Be more precise in describing what you have and what you are looking for.

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I looked into Stiebel Eltron heat pump hot water system before settling on another system that uses a built in timer. AFAIK, it has a simple relay contact input that you can connect to a “switch”. When it’s closed, it would run (or is it the other way around). Fronius inverter has a built in such relay so you don’t even need openhab.

However, you could hook this up to a relay that you can control via OpenHAB, usually via mqtt, e.g. Tasmota. This feature, AFAIK is a standard thing without any extra addons for the Stiebel Eltron. I might be wrong though, as I didn’t end up getting it so this is just based on their web site somewhere.

As far as OpenHAB goes, you get to know the current PV generation, and with a smart meter, know the usage and how much draw / export to/from the grid, and then Openhab / your rule can make the decision to trigger that relay.

You’d probably need a failsafe mechanism in case openhab is down.

For me, the built in timer on my heater is easier, albeit dumb, but the hot water system doesn’t run for a long time anyway.

Hi Martin,
do you use a Stiebel Eltron Heatpump connected and controled with openhab?
I am on the way to get information from my PV (RCT Power) via modbus. My Stiebel Eltron WPF 7 cool has a ISG and i use a mqtt setting to read required information. Control is a bit more tricky, but i am on a good way !
Best regards

Are you aware of Stiebel Eltron ISG - Bindings | openHAB ?

Hi Markus, yes I try to use it. But it does not support all required values I expect. I create a request for it (my first one ). But I have now idea if or when somebody check that :

We will see.

Best Regards