question

kallenr avatar image
kallenr asked

limiting power back to the grid with ESS (Multiplus-2)

is there a way to limit the Mutliplus-2 so that the ESS installation sends max. 60% of the power of the solar panels back to the grid once the battery is 100%?

This is mandatory in Belgium for a home battery from March 2021 in order to be eligible for a subsidy from the government.


I don't have a Fronius inverter !, but an SMA sunny boy.
Both AC outputs are not connected, a backup system is not necessary.
Possibly by connecting the solar inverter to AC1 out?

ESS
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3 Answers
woliver avatar image
woliver answered ·

Is all your solar power AC-coupled parallel the MP2 AC-IN? Or do you have also DC-coupled solar?

How much is the max. kWp and how much is the max. inverterpower of the sunny boy?

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kallenr avatar image
kallenr answered ·

at the moment it is parallel to the AC1 INPUT indeed, but I can easily change that.

The Sunny boy's power is 2500W, the Multiplus-2 is 5000W

I understand that the power of the solar inverter must be less than or equal to the multiplus.
there are no further DC panels or other inverters on the installation.

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woliver avatar image
woliver answered ·

The only way should be to set a charge rule in the GX to reduce the feed-in peaks so that you only load in this time with known peaks. But when the battery is at SOC 100% it wouldn't help.

Frequency shifting is only available for Fronius inverters so it makes no difference for your sunny boy wether you connect it to the AC IN or the AC OUT of the MP2.

Maybe there is the possibility to set the power directly in the sunny boy to a hard limit? For example if you have 3kWp then set the sunny boy inverter to 1800 W inverter power to get the 60% rule.

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