OpenEnergyMonitor Community

My Solar Use and Grid display odd

This is my first day with solar on so I already had My Solar feeds setup to capture it. I have an odd thing occurring that I noticed. On the bottom of the display there is Use, Solar, Direct, Export and Grid. I noticed my Use was slowly going backwards and Grid import is now 0 at the end of the day. I can’t seem to sort out why that is occurring.

The feeds that are used.

The solar input.

House usage.


Just to follow on, based on what I can see and the little I can find on how My Solar works I am hoping maybe someone (a developer?) might be able to give me more incite.

What I’m seeing is the Use gets subtracted from by the solar excess (export). This also subtracts from the grid (import). I’m not sure is Solar, Direct or Export are affected in any way from this since they reset at midnight and I don’t catch it if they do.

I was thinking Use would be my daily use on the panel (house use) and only count up. Solar would count up on what the solar generates. Direct would be how much solar directly gets used by the house and count up based on that. Export would be how much excess solar is sent out and count up on that. Grid would be how much is imported from the grid and count up from that.

So, is the subtracted working as expected or is there a mistake in one of my feeds?

This should help you figure it out:

Thank you, will take a look.

Also, The Solar is also going down. Was 32kWh and is now 29kWh.

Wonder if I might have been missing the Allow Positive from my Solar Import. Added that and will see what happens tomorrow.

Spoke to soon. My Solar kWh is dropping now that there is no solar being produced. What in the world is going on behind the scene?

You seem to be using an IotaWatt, what values is it providing on the Inputs?
Are those values correct?

If you look at your Inputs and your feeds in real time are they what you expect? If not, maybe provide some more detail about what they are and what you expect them to be…

The My Solar App just uses what is in your feeds, so if there’s incorrect data in your feeds, there’ll be incorrect values in the My Solar app.

I actually have 2 IotaWatts due to my setup. The Main one has been in use for a while now and the data provided is good. I actually am providing the My Solar app it’s main (house) use information. The 2nd IotaWatt is for solar. I have been monitoring it to verify the CTs are how I want them based on what the power shows on while way it’s flowing. That appears good. All I have it doing for sending the information is summing together the 2 CTs information and sending that. That is my solar feed. The rest of the math is done in EmonSD.

IotaWatt Solar output:

Nighttime here. So power should flow to the solar for the control computer.

Primary IotaWatt (house)

This has been working for a long time now and is verified.

I noticed when I put the allow positive my Use and Solar began to subtract. Think it’s an input that is messed up on the solar import. Removed it and as before, only Solar is subtracting.

Can you include some graphs of the feeds you’ve targeted in the My Solar App?

Certainly, I’ve been going through these to try to get an understanding on what is happening.

So, first up here is what is being fed to My Solar.


Solar Watts, I do want to note. That one will read -6W when the panels are not producing due to the control computer pull. I think that might be one of the areas that causes a slight slow issue overtime.




They all look ok to me.

Perhaps it is simply confusion about what the fields at the bottom mean? Those labels at the bottom are totals for the period you have in view in the graph.

I see that your consumption was 100% serviced by solar, so you would expect Grid import to be 0.
The view is also a sliding window, so if you had higher consumption at the start of the window and that “slipped off the left of the graph”, your USE value would be dropping.

Here’s my graph for yesterday for the 6 hours until the sun went down:

And here it is shifted forward in time by 2 hours, where that peak of usage at about 13:30 is no longer in the view:

My USE is down from 4.9kWh to 3.4kWh and my GRID is now up from 0.3 kWh to 1.7 kWh

I think your App and your feeds are all working exactly as required.

Hopefully that helps!

It is probably also worth adding that the numbers at the top are real time numbers, unrelated to the period presented in the graph.

Ok, yes that helps a lot. I was suspecting it was something like that, but just couldn’t confirm based on what I was seeing. (Honestly, didn’t notice that change when I zoomed in to 1 hour while working to smooth my PV Divert out).

I planned to do some dashboard work to capture my daily numbers in there which would be fine by me.

Hopefully some of the tweaking I did behind the scenes on the data (ensuring the -6W reverse power that goes back to the solar control) doesn’t get fed into the daily solar kWh made.

Thank you for the explanation.