ET112 + Current Transformer - AC Loads reading

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mysik asked Jun 20, '22

ET112 + Current Transformer - AC Loads reading

It's been a known fact that ESS system with ET112 as grid meter is responding very slowly to high load change and that the same system with CT clip is responding much quicker.

On the other hand ET112 is much more accurate in terms of energy usage calculations.

I thought it will make perfect sense to use both... CT to get fast responds and ET112 to get accurate grid usage readings. So I've wired up my system like on the diagram below:

I've noticed that after connecting CT to Multi I'm getting fast responds to load as expected but, on the VenuxGX diagram my AC Loads has not been calculated correctly (the actual load is about 800W), the meter settings is set to Settings-->ESS-->Grid Metering-->External Meter

Correct diagram, but AC Loads inaccurate

So to get accurate AC Loads readings I had to set Settings-->ESS-->Grid Metering-->Inverter/Charger, and now I'm getting accurate readings on the AC Loads, but the diagram is incorrect:

AC Loads correct, but wrong diagram

Is there a way to use both ET112 and CT clip and set this up to show correct diagram with correct AC Loads readings?

ESS Energy Meter ct

ess-with-multiplus-ii.png (231.7 KiB)

1655761099450.png (58.9 KiB)

1655761151072.png (56.3 KiB)

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Jason - UK commented · Jun 21, 2022 at 07:39 AM

I've always thought the same, CT sensor or response time, meter for accuracy but having this option for all connected items inc PV. Following with interest.

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h-copter commented · Aug 22, 2022 at 05:40 PM

Can I just check something: is it OK to run the system with just a 1 CT on the grid connection? The reason I ask is that my grid connection is distant from where I plan to install the MP and so I plan to use a CT and extend the wires with a twisted pair. I also have grid-tied PV on the grid side of the MP. Do I need another CT on that as well? Thanks

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mysik answered · Jan 31, 2023 at 05:27 PM

Final Update and Summary:

The idea was to use ET112 (for better usage accuracy) and CT clip at the same time (for better Multiplus response to sudden load change). My system setup is in the first post so for details how ET112 and CT clip is connected please have a look on the picture in the first post. To get correct AC Loads calculation you need to change the settings to:

1. ET112 --> Setup --> Role --> Grid Meter

2. Settings --> ESS --> Grid Metering --> Inverter/Charger

3. Settings --> PV Inverters --> Inverters --> "Inverter Name" --> Position --> AC Output

After this change all my loads calculations are correct, the only disadvantage is wrong diagram on the display, but it doesn't matter to much. My system has good respond time to loads change and good accuracy of used energy which was the main goal for my.

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goncalo commented · Feb 08, 2023 at 10:07 AM

What happens if grid power is lost? Does the Multiplus disconnect correctly? I'm asking because the behavior should be different between having loads on AC-in vs AC-out (as it thinks it has now)

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Modifications Space

Node Red Space

Answer 1 · 2022-06-22T08:14:53Z

mysik answered · Jun 22, 2022 at 08:14 AM

UPDATE:

I was wrong about correct AC Loads calculation when the setting is set to

Settings-->ESS-->Grid Metering-->Inverter/Charger

As you can see from the screenshot, the energy that Multi is using to charge batteries is been added to AC Loads, so the calculation is wrong.

Anyone in the community is using ET112 and CT clip at the same time???

Maybe someone from Victron can answer the question if it is possible to use ET112 as grid meter and at the same time CT clip connected to Multi to get better respond to loads?

Would be great if we could use both at the same time and having correct diagram displayed and correct loads in the VRM Portal/GX Device

1655885275985.png (32.0 KiB)

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Answer 2 · 2022-06-22T08:46:24Z

cookiemercedes answered · Jun 22, 2022 at 08:46 AM

I checked the files after downloading the new drivers from ET112 configure but found nothing new because I don't know enough about Windows to thoroughly erase the old ones foodle

Which subfolder did you manually navigate to? Contrary to expectations, I have a hunch that it was RT112 for me. https://wordwipe.io

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mysik commented · Jun 23, 2022 at 07:26 AM

What are you talking about?!?!

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Answer 3 · 2022-06-22T10:55:03Z

paulo-m answered · Jun 22, 2022 at 10:55 AM

I'm having the same problem (also on ESS). After adding the CT between the ET112 and the inverter to improve inverter response time, the AC loads reading is all over the place. This works well when the PV is not generating but once the sun is out...

Also the diagrams now show the loads on the AC out when they are all connected to the AC IN. This does not bother me as the inverter response time is now snappy but the readings on the AC loads needs some work.

My settings:
ET112's as grid meter and PV inverter on AC IN.
CT clip: Settings-->ESS-->Grid Metering-->Inverter/Charger

1655894660162.png (30.1 KiB)

1655894763995.png (36.4 KiB)

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Answer 4 · 2022-07-23T19:29:01Z

paulo-m answered · Jul 23, 2022 at 07:29 PM

update:
I've managed to fix the loads reading by moving in the settings the ET112 on the PV inverter to the "output" instead of in the "input". This works for me now as I only have on PV inverter on the system, but may not work with more. Ideally this should be fixed in code to match the physical setup but for now it kind a works.

What I've now noticed is that any current from the PV inverter to the batteries now counts as "consumption" on the VRM portal.

Can the clever programmers at Victron please fix this? Thanks

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Answer 5 · 2022-07-25T21:51:08Z

zivillian answered · Jul 25, 2022 at 09:51 PM

For me it doesn't even work at night:At midnight my battery supplies 1.2kW to the Multiplus, which (according to the image) converts it into hot air.

@Paulo M can you post a screenshot of the setting, which needs to be changed?

1658785597934.png (171.1 KiB)

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paulo-m commented · Aug 03, 2022 at 08:49 AM

@zivillian My problem may have been different from yours. I had readings but they were not close to zero. Also read my latest update below for where the cause of my problem was.

How is your system connected? Simple parallel to grid with everything on the AC input? What are you using as grid meter? Do you use a current sensor?

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zivillian paulo-m commented · Aug 15, 2022 at 10:16 AM

My setup is grid parallel, so the Multis are only connected at the AC Input. I'm using an Eastron SDM72Dv2 as grid meter and have added three current sensors.

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Answer 6 · 2022-08-03T08:45:40Z

paulo-m answered · Aug 03, 2022 at 08:45 AM

another update:
It seems that the incorrect consumption reading after configuring the PV meter (ET112) on output was my mistake as I forgot to tick the "use external current sensor" setting after adding the current sensor. This messed up all the readings. The problem I now have is that I can't move the PV meter setting back to the AC input where it belongs. The setting is stuck on AC output.

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Answer 7 · 2023-02-10T18:06:07Z

zivillian answered · Feb 10, 2023 at 06:06 PM

That's interesting - when switching Settings/ESS/Grid Metering to "Inverter/Charger" the readings are correct, but I also get an additional DC Power:

1676052361531.png (273.9 KiB)

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