Solar utility surplus not correctly calculated after switching CT's

I have 400A service with 2 x 200A panels and solar.
I have one Sense on 200A panel 1 with solar.
I have a second Sense on 200A panel far away from panel 1.
Sense does not support 200A + 200A + solar, thus I have two sense units.
Sense does not support multiple sense units on the same account, thus I have 2 sense accounts.

Per advice in this thread:

I connected the CT’s of sense with solar to the 400A side of the service panel.
This will let me use a singe sense, to monitor 400A service and solar.

After I moved the CT, keeping current direction the same (sticker side to supply), the sense behaved “weirdly”.
My usage was reported at almost double my normal load, power cycling the sense did not correct.
I used the mobile app and reset the data, the app asked me to power solar down and up, like I did when I first installed.

Problem is still that solar and usage are not correctly calculated.
If e.g. solar is producing 2KW and 1KW (-500W + -500W) is fed back to the utility, the usage is 1KW (2KW - 1KW), but the web app and mobile app reports usage as 0W, wrong, while the monitor page on the web app shows solar: 1KW/1KW, Mains:-500W/-500W.

I contacted support, but they take a) three days to respond and b) are not helpful, not reading my linked forum post and not reading my email, just pointing me to the supported panel support configuration page.

Here is a picture demonstrating the issue:
https://1drv.ms/u/s!AqeqhT0NczrNlJoVYxbMWjTuTWqNvg

A few questions:

  1. My understanding is that L1/L2 voltage and L1/L2 current is auto detected, i.e. swapping the CT’s does not have an impact. Is this correct?
  2. The CT direction is not important, just that CT1 and CT2 face the same direction. Is this correct?
  3. Is my assessment that negative current means solar feeds the grid, and positive current means the grid feeds the house, correct?

Any ideas, or is a factory reset a better choice?

I also have 2 x 200 A panels each with solar. 1st panel and that sense working perfect. 2nd panel and sense not working. I can see my mains and when solar is producing it is going negative. I have also reached out to Customer Support. I was not able to do that "turn inverter off, then on thing. Even though I turned off, the process hung waiting for me to turn it off. Odd. I am sure the support team will figure it out and provide a solution.

Can you try sketching out your power feeds and panels. and where you have the Main CT’s and the Solar CT’s? You can include the other Sense if you want, but since that Sense won’t impact how the first is running, lets ignore it for the moment.

So you have the Main CT’s on the 400amp lines on the Service Panel.
Where are your Solar CT’s in relation to the main CT’s.

Since you already did a data reset, lets not worry about how it was hooked up. The system is going to need to be recalibrated. Also, once you reset your data, don’t go messing with the CT’s. There are automated process’s that try to figure out which leg of power they are on and which direction they are facing. I would even suggest NOT setting up your solar until the Sense makes it through the signal check.

Hmmm,
The auto sensing of CT polarity and L1/L2 happens when you first do setup. It’s been so long since I have been through that process, I can’t remember what it takes to force Sense to to go through initial mains CTs setup again. I can tell you that a working Sense on a 400A main with Solar, shouldn’t have negative numbers on the mains… Here’s a view from mine

Setup Before:
400A_Service_Feed → Utility_Meter → 200A_Panel_1 + 200A_Panel_2
Sense_1_CT → 200A_Panel_1 ← Sense_1_Solar_CT ← Solar_Inverter
Sense_2_CT → 200A_Panel_2

Setup After:
400A_Service_Feed → Sense_1_CT → Utility_Meter → 200A_Panel_1 + 200A_Panel_2
200A_Panel_1 ← Sense_1_Solar_CT ← Solar_Inverter
200A_Panel_2

Net-net a single Sense now measures all power, on a 400A rated circuit, even though the Sense CT is 200A rated.

This means to me that you are drawing power from the grid.
What does the values look like when you produce more solar than you consume, I’d expect negative mains numbers, i.e. feeding the grid.

I’m pretty sure the Mains in the Signals section reflects Total Usage (the mains into your house as shown in the Power Meter), not the net. If I look at the Power Meter at the same minute that I captured that screen shot (4:42PM), it’s pretty clear that the Signal Mains align with Total Usage.

If Mains were based on Net Usage, they would be very close to zero.

Ok great. So basically I think you should reset your data and start the setup process again. I would suggest doing it at night when there is no solar being generated.
Skip the solar part of the set up. Let it get through signals check (i’ve seen it take 6 - 48 hours). Once it is happy, then go back and do the solar setup.

I suggest doing the initial setup at night so that during the first couple hours of it doing its checks, there is no possibility that you will start over producing on Solar which would push back to the electrical grid which can confuse the polarity check part of the Signals process. (this is my own opinion, not anything support has said).

2 Likes

Support fixed my set-up remotely- all is working as it should. THANK YOU :vulcan_salute:

Same here.
I got a message from support that they made a config change, and looks like things are now working as expected.