question

raphael303 avatar image
raphael303 asked

is the "AC Load" role for meter not implemented smartly on Venus OS?

I have an ESS with Battery, 3 phase multiplus, all loads on critical loads.

3 Phase solar inverter also on critical load output. no vrm implementation possible, I think.

ET340 directly after grid. Role: Grid Meter

ET340 on the critical load output of the multiplus but AFTER the solar inverter. Therefore measuring ONLY load. Role:??? Only "AC Loads" makes remotely sense.

VRM Dashboard: Makes no sense at all:

1668845751938.png


As you can see from the MQTT read out of the AC-load (role) meter, the power it measures is not reflected on the dashboard anywhere. "AC Loads" on the dashboard has been fluctuating around 0 to 100W since day one, which never made any sense since those outputs of the multiplus are DISCONNECTED. Critical loads is 0 which makes sense, because in the moment shown above there was about 2100W of solar power. 1700 went into the battery, 450 were used by the loads in the house. As observable from the mqtt read out.

However the dashboard in VRM has none of it. The "total consumption" read out is complete nonsense since day one and still makes no sense at all.

Here the device list, to demonstrate the meters being correctly recognized and setup:
1668846083307.png


In my opinion there are two possibilities:

There is somehow somewhere a hidden setting to tell Venus OS what the "AC Loads" meter is exactly. But where?

This is simply a bug in the implementation, which is unprepared for a situation where all load and PV is on "critical load" and a load meter is being used to separate PV from Load.

Why do I not put the meter to the PV?

Because the critical load measurement of the three multiplus in 3 phase mode (by night) is not precise. It seems the multiplus have trouble with precise read out.

Furthermore only like this I can measure energy use of the loads alone.

And I do have read outs from the PV, just not in VRM, but in homeassistant, which is ultimately where I need all data.

cerbo gxEnergy Meter
1668845751938.png (704.2 KiB)
1668846083307.png (119.5 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

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

Hi @Raphael303,

Indeed it's not implemented as you expect it to be here - and I agree that it would be better if it was, but for now it isn't.

The solution is to change the setting (and wiring) of the energy meter to be a PV meter, you can then assign the location of this PV meter to be on the output.

The multi will then see how much power is flowing in or out of the AC output, and subtract the production of the PV accordingly, revealing just the load remaining.

This is available as a system value, and should be presentable in home assistant - but that side is unsupported and may need some fiddling on your end.

The accuracy like this should be good enough for most applications.

2 comments
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

gloitom avatar image gloitom commented ·

Hello,

a year later, has anything changed, or is an AC Loads meter still not possible?

0 Likes 0 ·
Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ gloitom commented ·

Hi @gloitom,

Configuring an energy meter as an AC loads meter is possible, but it does not support all possible permeations.

If you could draw a diagram of your system and where you propose to put it, and what kind of output you're wanting from it, I can let you know specifically if it is supported in that configuration or not.

There is also a bit of documentation here, but we can always make it better -https://www.victronenergy.com/media/pg/Cerbo_GX/en/connecting-victron-products.html#UUID-219a875a-5193-e157-a2a6-c822c1521a4c

0 Likes 0 ·
raphael303 avatar image
raphael303 answered ·

Thank you very much! It really helps just to know, that it is not implemented like that. I will think about having the meter switched over.

But also I think during the day it will not work as I want it. Because during the day the multiplus critical load reading is 0. I don't think it will show "missing" power when it knows the PV-power. Because if it was to do so, it would have to show –(minus)something when there is excess and than subtract PV-power from that to reveal how much the load is subtracting from PV.

I was reluctant because I've read somewhere here, that the AC-Power readings from the multiplus are inaccurate on 3-phase situations and also found my own observations.

Presenting (any) CerboGX system values on homeassistant via MQTT was very easy and I can read out everything. I highly appreciate that possiblity thank you for that!

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

shaneyake avatar image shaneyake commented ·

The critical load reading will never display –(minus), only 0. This is done is software as the critical load reading is just a calculated value and not a measurement.
If you have the Meter on the PV it will display the correct valve but may not be as accurate as you want because it is a calculated value with AC_IN + Inverter_power = critical_load

0 Likes 0 ·
nuxland avatar image
nuxland answered ·

I have grid parallel system and two ET340 meters, one before GRID and another before PV inverter.

And it calculates LOAD very well. In this picture I was also charging from grid because kw/h was very cheap :)

1669134680219.png


1669134680219.png (42.0 KiB)
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

raphael303 avatar image
raphael303 answered ·

Interesting. I have questions :)

How do you switch to charge from grid? Via scheduled charging?

How did you integrate the EV charging station? Does it excess charge?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

nuxland avatar image nuxland commented ·

I do not have EV car yet (will arrive in march 2023).

I'm using Grid Setpoint and are setting it via node-red (I have created flow where I can set start hour and duration and Gridsetpoint value)

PS! Actually I have also changeover 64A switch in Victron Power cabine where I can change is my whole house behind Victron ac input or behind victron ac output 1. And I switched it over few weeks ago and now it looks like this. I had to configure Grid ET340 to be "ac out " and also EV charger to be "ac out" in venus OS.

1671207584304.png


0 Likes 0 ·
1671207584304.png (59.2 KiB)