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Tim D'hoe avatar image
Tim D'hoe asked

AC Load not always showing correct values

Ever since upgrading the Multiplus II to 492 and Venus OS to 2.82 (coming from 2.74), I have noticed that the AC loads are not always showing the correct values.

I often see AC load on phase 1 going to 0W.

It looks like it is cause by delays in reading out consumption values from either the Multiplus or the Grid meter. My battery cells are not well matches, so the BMS will start to constantly decrease and then again increase max charge current. So the Multiplus is constantly dropping and increasing the charge power quite a lot. Seems that, when u sudden increase or decrease occurs, it takes some time for the GX device to correctly recalculate the AC load.

Not sure if this is impacting anything other than the displayed statistics.

Anyone have any idea why this might be happening?

I have made a gif showing the issue. Note that power consumption is actually stable, so the AC load values are definitely incorrect.

test.gif

ESSpower meter
test.gif (617.0 KiB)
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Alexandra avatar image Alexandra ♦ commented ·
@timd93

You are viewing in the VRM, that could be affected by a whole lot of other issues related to lag and internet.

And maybe you have phase compensation on for the other 0W issue? It isnt a problem.

Dropping charge power is power control related as well? Are you using the CTs. There have been a few discussions about plugging and plugging them a few times to correct AC readings.

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Tim D'hoe avatar image Tim D'hoe Alexandra ♦ commented ·
Hey Alexandra

If I view it locally, so not on VRM, I see the same issue.

Phase compensation is indeed on, but that shouldn't cause wrong AC load calculations right?

I'm not using CT's, I'm using the EM24 ethernet version as a power meter.

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kevgermany avatar image kevgermany ♦♦ Tim D'hoe commented ·
There were bug fixes after 2.82. I think some to do with AC. Please try upgrading to 2.84.
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Tim D'hoe avatar image Tim D'hoe kevgermany ♦♦ commented ·
Just tried it, same issue
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10 Answers
Tim D'hoe avatar image
Tim D'hoe answered ·
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tsteinke avatar image
tsteinke answered ·

Hi there,

I've the same issue.

Multiplus 2 48/3000 product ID 2629 FW v494

Cerbo GX v284

2kWp AC-coupled PV on AC OUT1

At first Im using the external CT; then switched to EM-24. Issue remains the same.

Is there a solution available or in sight ?

Best regards

Thomas


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tsteinke avatar image
tsteinke answered ·

I finally found a Solution for me.

The installed EM-24 is configured as Grid meter.
In ESS configuration „Grid Metering„ is set to „Inverter/Charger“.

Now the display and values in remote console and VRM are correct.

Regards

Thomas

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Tim D'hoe avatar image Tim D'hoe commented ·
So what did you change? In my ESS, Grid Metering is set to "External Meter", as it always has been. What did you set your "Grid Metering" to?
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Tim D'hoe avatar image
Tim D'hoe answered ·

This issue is still present, and have had reports of at least one other person having the same issue.

@mvader (Victron Energy) Is this bug known?

For reference, using Multiplus II, Venus GX and EM24. Everything is on latest prod firmware.

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guenter93 avatar image
guenter93 answered ·

I also have this issue on my installation - wildly fluctuating AC Loads between 0 and 10KW
6x MP2 5000 in a 3 phase config, Cerbo GX, EM24 Gridmeter, 2x SMA Tripower 5000 AC coupled

16x Pylontech 2000 with low resistance DC cabling & busbars

ESS standard mode, currently no AC out connection

Austrian grid setting, low impedance grid connection only 20m from street transformer

Everything on latest Firmware

resetting MP2 or Cerbo does not help more than a few minutes

System stabilises after 5-10 Minutes and starts fluctuating again later

During this event the loads are about 3kw, pool pumps, irrigation pumps, household appliances


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guenter93 avatar image guenter93 commented ·

Is there any news on this ?

This is really annoying as the fluctuations happen almost every day for hours !

The displayed AC loads are complete nonsense - and ESS seems to follow those wrong values and wasts lots of PV energy

I would be happy to assist in troubleshooting and retrieving additional infos

I am an electrical engineer with most measuring tools available

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felr avatar image
felr answered ·

I'm also having this problem with my installation. When the battery is charged to 100%, AC Loads starts acting weird and oscillates between far too high and low rates while the real load is constant.

My setup constists of 3 Multiplus II 48/5000, two MPPT charge controllers and a Fronius 3.7-3-M PV Inverter. ESS is set to zero export with 200 W of constant power draw. All metering is performed by the Multiplus units.


2022-08-13-16-42-45.mp4 (26.7 MiB)
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ted avatar image
ted answered ·

Could it a problem with L1-L2-L3 Rotation at the EM24 or so?

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ted avatar image ted commented ·
Or different L1-L2-L3 allocation in the Multiplus 3 Phase Settings?
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ted avatar image
ted answered ·

I found the problem. You have a L1-L2-L3 Order in the EM24 as well as in the Multiplus 3-phase settings.


Check that the EM24 has the right Phase order (Display View in EM24) and check the wires of the Multiplus . I had to reconfigure the 3-phase settings of the Multiplus (you need to add the assistants after this again)



To clarify. How it can happen?

I had at the beginning L1-L3-L2 at the EM24 (but did not check the phase overview at the EM24 or cerbo). But my wires to the 3 Multiplus were right. So I did configure L1-L2-L3 in the MP settings. I got after this a phase-rotation error and did try L3-L2-L1 which did work for some reason. I thought that if the Multiplus recognizes the phases, then you can't do anything wrong here (phase rotation error), but that's not the case (see strange AC Load behavior)

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T F avatar image
T F answered ·

I have the same issue that AC loads are totally fluctuating.

3 phase each with a MP2 3000, EM 24 with RS485 as frid meter, additional PV Inverter with ET112 on ac in.


The system is not able to keep the set gridpoint but every 30s starting to see high (1000W) loads and then tries to feed in above 2000w into the grid.

Any guidance or checklist from Victron or the community would be greatly appreciated.

Tom

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Arno Broeders avatar image
Arno Broeders answered ·

1720518878488.png


I still have no inverter and batteries, but I bought a Cerbo GX to prepare for my ESS. I have a grid meter installed and the -4573W is correct. I have two meters for my two PV setups and 5257W is the correct accumulated value. The calculated AC Loads is not what it should be. What could be wrong?

My meters showing the right values:

1720519133635.png

Yesterday it was perfectly fine with less PV, values are updating every second.


1720518878488.png (27.9 KiB)
1720519133635.png (28.6 KiB)
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nickdb avatar image nickdb ♦♦ commented ·
The console is designed around an inverter, without one it will not work as expected, this is documented in the manual. You are also using unsupported plugins for the meter(s).

Wait till you have a full system and then try again.

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