question

savastnas avatar image
savastnas asked

VenusOs AC Loads calculation

Hi,

I'm currently setting up a Victron system. I don't have an inverter/charger yet but I did already install Venus OS on a Raspberry Pi, connected an EM24 Ethernet, my SolarEdge SE10k and Batrium. For some reason my AC Loads does always equal PV Inverter power. What might be wrong? Is it because I don't have my Multiplus yet?

The EM24 is set to Grid meter (it doesn't show up under "Energy meters" in settings, should it?), the SE10K is set to AC Output. If I use any of the other alternatives it disappears from both the Remote console and from VRM. The AC Loads changes to 0W, then.

venus.pngvrm.png

Ah, and btw, the EV Charging Station shows values which I translate from a Keba P30. That works! For some reason it doesn't show up in the Remote console, though. Should it?


ESSVenus OS
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5 Answers
savastnas avatar image
savastnas answered ·

Ah... hmm when the load is higher than the PV production (easy on such a sad rainy day...) the calculation is different! It's only when the load is lower that the AC Loads are calculated equal to PV Inverter.

But on the imag below? Hmm... PV Inverter 994 + AC input 281W = 1536W? Nope. Again the difference is the negative power on L3.

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victech-power avatar image
victech-power answered ·

AC loads are in general behind a Victron inverter. ( critical or non critical )
As you state you do not have one, the calculation could be different.
You are for instance consuming power in your ecosystem that is not "detected or measured" by a component in your ecosystem. So it can only "assume/calculate" your AC loads.
As your solar underproduced compared to load ,.. the figures seem more logical as you know see the result in the grid draw.

How did you integrate your SolarEdge ? Solar Edge includes its own inverting consumption to be shared to the API. Including the inverting consumption creates a loss which most people do not see. That is why I use a separate ET340 to know exactly what the net production is.

EV chargers indeed do not show up in remote console.

Wait for the inverter and program the position of your AC connected Solar Edge on the correct side of the inverter.

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savastnas avatar image savastnas commented ·

Yeah, I hope I'll get my inverter soon.

The EM24 is directly at the grid. So it measures both production and consumption combined. I figured btw that it states "AC input" instead of "Grid" as well. Maybe that's another symptom of me not having the inverter yet.

I'll begin with just one Multiplus. How will this turn out since it would be single phase?

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victech-power avatar image victech-power savastnas commented ·
You can use a 3 phase energy meter and a 1 phase Multi setup.

Make sure you connect the first Multi to the "true" 1st phase and not by accident to 2nd or 3rd as per the manual.
I have seen situations where the phases were swapped by the utility company.
In a 3 phase setup the Victron detects this as phase rotation error and will show on your GX but in a single phase setup you will not be informed.

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savastnas avatar image savastnas victech-power commented ·
Just to give feedback. I got three Multipluses 48/5000 in the meantime and it works as expected. Currently only one is connected since it's just a temporary test setup at my home office where I don't have access to three phase power. ESS works nicely!

I'll move everything to a proper location when spring will begin to arrive here in Northern Sweden.


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genscher avatar image
genscher answered ·

Hello!

I have the same problem!
I use a Cerbo GX and have a EM24 as Grid Meter (RS485 attached to the Cerbo GX) and a non-Victron 3-phase-energy-meter for my PV inverter (also RS485 attached to Cerbo).

As you can see, in certain situations, the AC load is calculated wrong. See phase 1+3 in my image. When the net load on a single phase gets negative, but there is also a phase with positive values, the AC load is calculated wrong.

As you can see, even the calculated net load reported by the EM24 is wrong: -75 = -67 + 38 -53 is wrong. It's -82.

Any ideas?

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mhinz76 avatar image
mhinz76 answered ·

Hi all

I have exactly the same issue. as soon as the power per phase produced by the inverter is high than the actual AC load (means, as soon as my EM540 power meter shows a negative power flow, into the grid), the AC load is not correctly calculated but just shows the inverter amount. (see picture L1 and L2).

I am using venus OS on Raspberry Pi version 3.11. So is this a bug or do I miss any configuration?

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi All,

Energy Meters are intended to supplement a Victron Inverter/Charger in the system.

Energy Meters are currently limited in their potential applications. Each Energy Meter is only intended to provide a specific piece of additional information - total loads on AC input and grid import/export, or AC PV inverter and AC generator production without network communications.

It is possible to initially use just a GX device together with an Energy Meter to determine and record the consumption, for example of houses/buildings, heating systems with heat pumps, ventilating and air conditioning or production facilities. Afterwards, the collected data can be evaluated and a decision can be made about the dimensioning of the required Victron inverter/charger(s), the solar system and the type, size and number of batteries.

With GX device firmware version 2.80 and later, they can also be used for other purposes e.g. to measure specific, arbitrary AC loads or circuits for example.

But this should not be considered a replacement to having a Victron Inverter/Charger. Attempting to use other brand battery inverters and trying to substitute their lack of data connectivity to the GX device by using Energy Meters will not work as expected.

This is a frequently asked question about our energy meter support and is extracted from that manual;

https://www.victronenergy.com/media/pg/Energy_Meter_EM24_Ethernet/en/faq.html

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