AC Load not always showing correct values

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Tim D'hoe asked Feb 26, '22

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.

ESS power meter

test.gif (617.0 KiB)

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Alexandra ♦ commented · Feb 26, 2022 at 12:51 PM

@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 Alexandra ♦ commented · Feb 26, 2022 at 01:03 PM

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 ♦♦ Tim D'hoe commented · Feb 26, 2022 at 02:34 PM

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 kevgermany ♦♦ commented · Feb 26, 2022 at 03:56 PM

Just tried it, same issue

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Tim D'hoe answered · Aug 11, 2022 at 01:47 PM

@Guy Stewart (Victron Community Manager) @mvader (Victron Energy) @Daniël Boekel (Victron Energy Staff) @Thierry Cortassa (Victron Energy Staff) @Johannes Boonstra (Victron Energy Staff) @Thiemo van Engelen (Victron Energy staff) @Martijn Coster (Victron Energy Staff) @jperez (Victron Energy Staff)

If anyone could look in to this issue, or provide any feedback as to why we are seeing this, it would be greatly appreciated :)

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Modifications Space

Node Red Space

Answer 1 · 2022-04-18T16:44:36Z

tsteinke answered · Apr 18, 2022 at 04:44 PM

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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Answer 2 · 2022-04-21T20:43:04Z

tsteinke answered · Apr 21, 2022 at 08:43 PM

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 commented · Jun 28, 2022 at 11:44 AM

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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Answer 3 · 2022-07-29T09:55:20Z

Tim D'hoe answered · Jul 29, 2022 at 09:55 AM

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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Answer 4 · 2022-08-02T13:50:18Z

guenter93 answered · Aug 02, 2022 at 01:50 PM

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 commented · Aug 09, 2022 at 11:32 AM

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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Tim D'hoe guenter93 commented · Aug 11, 2022 at 12:23 PM

Not that I know. Have not heard anything from Victron on this, they are NOT looking in to it as far as I know

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Answer 5 · 2022-08-13T14:49:28Z

felr answered · Aug 13, 2022 at 02:49 PM

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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Answer 6 · 2022-10-29T07:48:00Z

ted answered · Oct 29, 2022 at 07:48 AM

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

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ted commented · Nov 09, 2022 at 10:16 AM

Or different L1-L2-L3 allocation in the Multiplus 3 Phase Settings?

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Answer 7 · 2022-11-14T07:09:34Z

ted answered · Nov 14, 2022 at 07:09 AM

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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Answer 8 · 2023-05-08T06:45:55Z

T F answered · May 08, 2023 at 06:45 AM

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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