Solar math is wrong

[sebxx]

I have a small solar setup 1 panel,

 

During the day, I can see it’s generated power added to the main use onto the balance: that’s expected.

But at night, the micro inverter draw is also ” added” as if it was generating energy 🤯

I wish I had night generating panels, but it looks like the value is incorrectly handled in the calculation.

[djwakelee]

Known issue.  They only measure current one way on the circuit clamps – load or generation.  As a result, night-time inverter and/or microinverter dark power draw is falsely shown as generation.  They’ve said before that they could properly show this, but they don’t seem to be addressing any bugs or feature requests for the Vue 2 – for whatever reason.

[sebxx]

I guess I’ll return the Vue kit, too many basic feature/bug are not being worked on.

[djwakelee]

Sadly, this is the case.  The Vue 2 product has great potential at a good price, but Emporia seems to have abandoned supporting it.  They no longer reply to this forum either.  It you can deal with the issues, it is a good value.  But it is disappointing how many things like this were promised to be on the road map, but dates came and went without any changes.  Seems like all effort has gone to the EV charger, and nothing on the Energy monitor.

[sebxx]

I wonder how much is doable from HomeAssistant without the Emporia cloud

[m4lc0lm]

Its a similar issue to monitoring a battery, can only look at that in the one direction which is a shame. However I guess that with some manipulation in Excel with downloaded .csv data that may be fixable. Having said all that it is a very useful tool as our solar monitoring app from Moixa has questionable accuracy so having two or three different monitoring sources does help.

[sebxx]

I don’t think it’s correct to say it can only measure in one direction, else there would be no arrow on the CTs.

I think the app doesn’t consider the signed value correctly, I suspect it converts to unsigned which causes the issue I raised.

[djwakelee]

The CT’s are indeed able to determine the direction of the current flow.  It is either the hardware or cloud that converts it to an absolute value for both loads and generation, then sets to positive or negative based on circuit type (solar generation or not).  Not sure if it is hardware or cloud – but it isn’t the app as the same problem exists if you download the cloud data.  Some people have installed the circuit CT’s in the opposite orientation, since that can fit the wiring better in tight electrical panels.

• This reply was modified 2 years, 1 month ago by djwakelee.
• This reply was modified 2 years, 1 month ago by djwakelee.
• This reply was modified 2 years, 1 month ago by djwakelee.

[sebxx]

It can’t be the hardware, else there wouldn’t be an arrow to begin with… When I say app, I mean their software stack, so what you download is already processed there

 

[djwakelee]

If they ever did use current direction, yes the arrows matter.  It does matter for the mains, where they show +/- consumption.  But for the circuit clamps, as mentioned, you can presently install them either direction.  The arrows don’t matter – until they decide to provide bi-directional info.

Yes, it could be the cloud where they are taking the absolute value and reconciling with circuit type (solar or not), but it could be the hardware / firmware that is implemented in the Vue 2 also.  At a low level, they have an Atmel microcontroller that does the power measurement.  Then have and ESP32 that talks to it, and communicates up to the cloud (Amazon AWS MQTT, from what others have investigated).  At the lowest level, the Atmel part is able to know the power flow direction, phase voltage, power factor, etc.  Who distills that down to lesser information is not clear.  So when I say the hardware may not present the info, I mean the hardware / firmware that is in the Vue 2 – versus something on the cloud or app.  Unlear what in the hardware can be firmware updated.  They may only be able to update the ESP32, and the power measurement microcontroller may not be.

A related example.  Initially the Emporia app didn’t display Amps.  Emporia added this based on popular customer request (one of the rare times they added a feature), but they did so by merely dividing the real power by 120V.  Two problems with this: 120V may not be 120V, and real power can’t be used to get Amps without power factor.  So the amps shown on the app is only accurate if you have resistive loads, and exactly 120V.  And the reason they did this is because the Vue 2 doesn’t communicate Amps to the cloud – only real power.

If they updated the device firmware, cloud, and app – this product would be so much better – without the bugs and a few basic features that are lacking.  But their focus seems to be a new revenue and products, and not making existing products better.

• This reply was modified 2 years, 1 month ago by djwakelee.

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