question

maha avatar image
maha asked

MultiGrid don't use MPPT when battery reached 100%

In my ESS-system a Fronius Symo 8.2 is at AC-in and a MPPT250/100 at AC-out. When DC feed-in is disabled and the battery has reached 100% no power comes from MPPT but all from the Fronius.


Only when the Fronius no longer supplies sufficient power does the MPPT switch back on. This is how I lose feed-in remuneration. Is it possible to prefer MPPT-power for critical loads?

MPPT Controllersdc systemmultigrid
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1 Answer
service-team-doebeln-gmbh avatar image
service-team-doebeln-gmbh answered ·

You work with zero feed. The battery is full. Only when the performance of the AC-coupled PV inverters of Fronius is exceeded and network reference is registered, the MPPT starts again.


Sie arbeiten mit Null-Einspeisung. Die Batterie ist voll. Erst wenn die Leistungsfähigkeit der AC-gekoppelten PV-Wechselrichter von Fronius überschritten und Netzbezug registriert wird, setzt der MPPT wieder ein.

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maha avatar image maha commented ·

@Guy Stewart (Victron Community Manager)

Danke für die Antwort, aber das ist mir bekannt. Die Frage bleibt:

Wie kann ich dafür sorgen, dass der Strom für "critical loads" vom MPPT genommen wird und nicht(!) vom AC-in gekoppelten PV-Inverter. Durch die jetzige Betriebsweise wird unnötigerweise die Stromerzeugung des MPPT abgeregelt und so Strom vom PV-Inverter verbraucht, den ich eigentlich einspeisen könnte und dafür Vergütung erhielte. Derzeit geht mir Einspeisevergütung verloren und für den vom Fronius erzeugten selbstverbrauchten Strom muss ich auch noch Steuern bezahlen, denn dieser Strom ist als steuerlicher Ertrag zu versteuern (nicht zu verwechseln mit EEG-Umlage).


Thank you for the answer, but I know that. The question remains:

How can I make sure that the current for critical loads is taken from the MPPT and not(!) from the AC-in coupled PV inverter. The current mode of operation unnecessarily regulates the power generation of the MPPT and thus consumes power from the PV inverter, which I could actually feed into the grid and receive compensation for this. Currently, I am losing feed-in remuneration and I also have to pay taxes for the electricity I use myself and which is generated by Fronius, because this electricity is taxable as taxable income (not to be confused with the EEG levy).


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Martin Gasthuber avatar image Martin Gasthuber maha commented ·
Hi,


any solution found for that problem - i do have the same observation and would like to maximize the AC-In connected PV Inverter feed and run the house internal loads through the MPPT (DC connected solar charger) via the 3 Multiplus

best regards,

Martin

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