question

I have also a ET112 measuring a small inverter (EVT560) and observe sometimes, that the ET112 shows 1W. But not always, it sometimes toggle between 0 and 1W.

I assume, that this might be the self consumption of the inverter itself that is displayed as production. Don't know if the ET112 can display a consumption in the PV meter configuration, or if it just turns "negative" consumption in "positive" production.

But what you could check, - you could disconnect the PV inverter at night to check if the consumption then drops to 0W.

@Jetlag

After reading your reply I checked the VRM log graph to see if it was a stable 2 Watt production or if it's fluctuating. It's showing a stable 2 Watt most of the time, but sometimes it drops to 1Watt to be back at 2 Watt straightaway. So yes... It could be the self consumption of the ET112 that somehow is converted to a positive number.

So I will do the test that you suggested en disconnect the inverter at night to see if the production goes zo zero. I have to be home to do that, but since i'm working offshore I have to wait until I get back. Will let you know what the result were.

If it turns out that that is the problem indeed then there is not much I can do about it it I guess. I can take it into account in my calculations, but in VRM it will still show.

The Standby consumption at night of your SMA inverter is figured with 1W in the datasheet.

So this might be it.

I assume that the value, the ET112 is delivering, is anyway inverted to positive in the victron system. With this, a wrong installation would not affect the reading of the power meter.

And the ET112 itself has definitly less then 2W of self-consumption.

Sounds plausible. But not really sure what you mean by: "With this, a wrong installation would not affect the reading of the power meter."

Wjen I'm back home I will do the test. I thing you are correct in saying that the ET112 will not consume that 2 Watt by itself.

The only thing left then is to accept it or ask Victron to make a fix for this somehow.

Thanks for your input in this! Its appreciated.

Did some testing and investigation. First a picture of the problem. Inverter "producing" 2 Watt in complete darkness.

Now a picture with the connection cut to the grid (wall plug removed from the grid socket)

So.... Its not the ET112. The energy meter is still connected to the grid and working. Its showing zero as it should.

The problem is obviously in the PV inverter itself. It is probably self consumption from the. Pv inverter that (I suspect) is converted to a positive number by the ET112.

Any ideas anyone?

For several years the same observation here with an SMA5000TL20 and ET112:

fluctuating positive values after sunset between 0/1/2 W.

I assume you don't have a solution? I also have a SB4000TL-21 but that one does not show that problem. To be honest..... Its not using a ET112 for sending its data towards VRM.

With this sentense "With this, a wrong installation would not affect the reading of the power meter." I mean, that the direction of the ET112 is not relevant. You can install the energy meter as grid meter or as PV generator meter. So you have to ensure what is input, and what is output on the ET112.

But what I guess is, that the VenusOS is always inverting the value to positive even if someone would install the meter wrong, and the meter would only deliver negative values, the VenusOS will turn it to positive. That's why the 1W or 2W of consumption of our PV inverters are always displayed as positive and never negative.

This does not solve the problem at all. This was just an idea I had as I observed the problem with my inverter.

A solution would be to allow some kind of offset, but this is rather unlikly.

An other solution could be some automated switch that is turning the inverter on/off at night. Someting like a WiFi Plug that is controlled via some assistnant (e.g. Alexa) according to sunrise and sunset...

@Jetlag

Thanks for the clarification. I understand what you mean now.

I think your right in saying that Victron probably won't make any adaptions or fix this (small) problem. The only way to go then is as you suggested. And that is a WiFi switch or something like that and switch the inverter on and off at a certain time with home automation.

I do have some plugs laying around and already doing some automation in Node-red. Will use a "big timer" in combination with a sun rise / sun set shedule. Cant be to hard.

Thanks for all your input. At least I know now that its not me and I'm not the only one.

It's just that I could not get it to work without the ET112. Otherwise I would try that just to see if it makes a difference. But I'm already at the latest update for that type of inverter and I just cant get it to work with modbusTCP. I'm missing the settings for TCP and UDP server in the Inverter. My other Sunnyboy inverter is a bit newer and has a software version that is one version newer. That works flawlessly.

So I guess that the combination sunnyboy / ET112 for monitoring PV production is not ideal for use in VRM and remote control.