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chris2 asked

Multiplus 2 fluctuations


Hello, Since the installation almost a year ago I have had problems with strong fluctuations on phase 1, where the PV inverter and Multiplus 2 are also connected.

These fluctuations can go up to several hundred watts for a short time. The fluctuations are also present at night, but not as strong.

No loads are connected to phase 1, but loads are displayed and actually consumed.

In the meantime I have separated all loads on AC-out1 and AC-out2 for testing. This brought no change.

The system is installed in Austria, the configuration for Austria programmed in Multiplus 2.


Here is a short video where you can see the fluctuations on L1 under AC loads:



I have no more idea why that could be. I would be very grateful for your help.

BR
chris



System is running in ESS optimized mode without battery life, no scheduled charging.

1xMultiplus-II 3000
Venus GX
EM24
3x Pylontech US2000 7,2 kWh
AC coupled PV-Inverter Fronius Primo 4.0 connected to AC-in


Multiplus-II
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4 Answers
Paul B avatar image
Paul B answered ·

have a look at the mutliphase regulation and read up on this. as this maybe you issue. its used to try and balance the phases, you can turn it off


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chris2 avatar image
chris2 answered ·

Hi, thanks for your answer.

That´s not the issue. I need to set it to "total of all phases".

Even setting it to single phase there is no difference. Fluctuations up to several hundred watts.

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chris2 avatar image
chris2 answered ·



Look at that strong fluctuations at L1 under "AC Lasten" . There must be something wrong. Normally it should be 0 watts since there is nothing connected !


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seb71 avatar image
seb71 answered ·

Is your system supposed to inject (feed in) power into the grid or not?

What is your "Grid setpoint" if not?

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chris2 avatar image chris2 commented ·

System is allowed to feed in.

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seb71 avatar image seb71 chris2 commented ·

Then what's the problem? It is feeding in.

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chris2 avatar image chris2 seb71 commented ·

Look at "AC Lasten" L1. There is nothing connected to L1. It has nothing to do with feed in. It seems there are loads connected to L1.

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seb71 avatar image seb71 chris2 commented ·

What current sensors you have and where are they placed?

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chris2 avatar image chris2 seb71 commented ·


An EM24 is installed directly after the electricity meter of the energy supplier.

I originally installed an ET340, which had exactly the same problems.

I had exchanged the ET340 for the EM24 because the ET340 had displayed incorrect values in the VRM portal.

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seb71 avatar image seb71 chris2 commented ·

No shunt for DC side (current in/out of the battery)?

Where there are no currrent sensors, the values are only estimated values.

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chris2 avatar image chris2 seb71 commented ·


There is no shunt installed on the DC side.

I can read the values on the display of the et340, and there I see these extreme fluctuations as well.

What does this problem have to do with the dc side?

I´m having an AC coupled PV-Inverter Fronius Primo 4.0 connected to AC-in.

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seb71 avatar image seb71 chris2 commented ·

The power the PV inverter feed in is estimated.

The power that gets into the battery is estimated.

Only the power that goes in/out of the grid is actually measured.

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chris2 avatar image chris2 seb71 commented ·

Can you tell me what type of sensors I need, and where to install to solve that issue ? Thanks in advance.

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