question

Lars Filusch avatar image
Lars Filusch asked

ESS, AC Loads, Grid Meter, Multiplus

Hey,

1x Multiplus-II AC In (AC Out not connected), EM24 gridmeter, Fronius PV Inverter, Venus GX.

On the remote console the Multiplus AC Power is always included in the AC loads.


for example the Multi is charging the battery with 1kW and the house consumes 500W, AC Loads is 1500W. AC loads should show only the house consumption w/o the Multiplus power...?


best

Lars


AC PV Coupling
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Tom Büschgens avatar image Tom Büschgens commented ·

In the given example: Are you charging the battery from grid or from solar?

And: Sure that the MP2 is connected to L1?

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Lars Filusch avatar image Lars Filusch Tom Büschgens commented ·

no it isn't, does it have to be connected to L1?

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Lars Filusch avatar image Lars Filusch Tom Büschgens commented ·
an other example, 2.7kw coming from Solar to AC, charging with 2.2kw to the battery, AC Loads 2.7kw. Grid 0W - real AC Loads should be 500W



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3 Answers
Tom Büschgens avatar image
Tom Büschgens answered ·

Hi @Lars78 ,

not 100% sure, but to my knowledge the AC Loads of the MP2 in the VRM portal (same for the remote console) is calculated using the difference between solar yield (per phase) and whatever the EM24 delivers (per phase).

So if you use L2, you will get wrong values for sure. Just simulated this here using my dbus-fronius-smartmeter setup and got wrong AC load values immediatly after exchanging L1 and L2 values.

So yes, make sure that the MP2 is connected to whatever the EM24 thinks is L1.

OTOH: It is just a calculated value for display - AFAIK it influence the stats in VRM.


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Lars Filusch avatar image
Lars Filusch answered ·

OK, i´ll give it a try. But in my thinking it doesn't matter.... because it's summing 3 phase power and single phase. And the Venus knows how much power the multi is consuming, so AC Grid + PV Power - Multiplus consumption = AC loads no matters the multi is connected to L1, L2 or L3.

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Tom Büschgens avatar image Tom Büschgens commented ·

Happy to learn how thing work out for you. And: It does matter. If you check this forum you will find quite some posts pointing out that when the MP2 is not connected to L1, the AC load is off.

You will also have the same effect during the night, when there is no solar yield / PV power at all.

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Lars Filusch avatar image Lars Filusch Tom Büschgens commented ·
ok, try to finde something about this before posting my question. But maybe i search for the wrong keywords...
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Tom Büschgens avatar image Tom Büschgens Lars Filusch commented ·
Sorry if it came across rude - this was not my intention. Rather to underline that this seems to be a known issue when running a single MP2 on any other phase than L1.


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Lars Filusch avatar image Lars Filusch Tom Büschgens commented ·

no worry, i can handle something like that (-:

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schollex avatar image
schollex answered ·

Hi, I am facing a similiar situation:

1672563333042.pngMy setup is:

  • MP2 on AC-in L1, another MP2 on AC-in L2. AC-out are not used.
  • PV Inverters connected to L1 and L2.
  • All components are configured knowing their phase.

In the picture you can see the PV Charger charging the batterie with ~1000W.
The remaining 600W charging power come from the PV inverters.

All shown values are correct, except AC Loads:
I expect AC Loads showing the power-consumption of my house excluding the MP2.
But AC Loads shows my house consumpiton including the battery charging done by MP2.

Bye

Alex


1672563333042.png (87.0 KiB)
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Tom Büschgens avatar image Tom Büschgens commented ·
So. you are using a "split phase" configuration in a three-phase setup, right? Some further insights about your exact configuration in terms of your MP2 would be helpful, I guess. Or do you have set up two independant ESS?


In your assumed setup I would expect L3 to be identical for GRID and AC-Load - but it is not. Sure that all phases are passed through correctly? Any ideas where THAT mismatch does come from?

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