Manually throttling Primo Fronius PV whilst running ESS

Q&A and troubleshooting
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If you’re running DESS (in Green mode with the Hack), the system will automagically throttle down the Fronius inverters when grid price is negative.

If you’re not running DESS or you want manual control, you’ll need to get creative in Node Red or HomeAssistant.
In this case you’ll need to somehow figure out when injection prices are negative and associate actions with it.
The options you have in Node Red:

  • PV Inverter Control: set the output power limit of the Fronius inverter
    You’ll need to calculate the PV Inverter’s maximum output to end up with zero feed in.
    Trick to know: you need to inject that value every ~30 seconds or so, or after a while it’ll default to max power again.
  • Settings Control
    Here you can set the Maximum System Grid Feed In power, or just straight (dis)allow grid Feed In of excess DC or AC coupled PV - this would seem like the easiest option.