Zero (0) power used?


#1

After getting my solar installation operating, I see some odd results on the data being returned. Overnight, when no solar was being generated, the power being used produced a valid graph and Sense Status page produced valid positive values for the mains and close to zero for the solar.

However, after the sun came up today, the solar values generated a lot of power, the mains zero (0) power (and thus no devices appear to be turning on and off on the graph), and the Sense Status page shows negative (-) power on the mains (which makes sense as raw data since the solar is generating more than is being used). See attached screenshots,






Note that this is with an Android phone and not IOS.

So the question is if there is a problem with the software, or if there is a setup/install issue?


#2

I would expect this in a couple situations - your main cts are reversed (they’re not, we’ve already decided that and the fact they look normal at night says the same), and two, your calibration got either mussed up or off track. I’ve seen both of the latter - needing to recalibrate and/or needing tech support to correct something on their end (because the calibration went OK - you saw normal curves yesterday, right?). I’m not sure, but I think my problems boiled down to a software glitch that had to be corrected on their side. Can you pinpoint a specific time when your mains swapped polarity?

Bottom line, I think you can try recalibration, but it may not be long-lived and I’d send in a ticket (I already know what you’re thinking) and ask that they find the error(s) associated with flipped mains.

If you were to do the math, your usage would essentially be solar plus the actual mains values, or roughly 700w.


#3

Yes they looked correct to me yesterday, and after the sun went down, although there may not have been as much sun as there was in the above screenshots vs my usage at that time. But I still have a few questions about the result 3406 Solar watts vs 2011 W and 2005 W shown in the Sense Status Solar line. Where did that come from? The main problem seems to occur when sun power exceeds current usage.

Also how do you recalibrate? Is that just going through the install again?

They seemed to swap polarity as the sun started to power the PV panels.

It feels like an android OS app issue to me, but we’ll see. Here is a screenshot after the sun was obscured by rain clouds this afternoon.


#4

Any progress? The recalibration can be done by going into the settings menu - sense monitor - solar. That’ll automatically trip you into a calibration so don’t go there til you’re ready!

Wish I could help more - if a recalibration doesn’t set you straight, I do think there’ll be a correction they need to make at support… Whether that’s software or…? I’m not sure.

I’ll have another look at your setup, though, it still seemed strange to me, not straightforward like mine :confused:


#5

Can you take a pic of your main panel again? (now that you have the solar leads on correctly) I have a thought and just want to see if I’m on the right track…


#6

I’ll try to take another picture tomorrow of the power panel, but we are having a storm tomorrow, so they’ll be no solar.

Incidently the solar power comes in from the lower left side, the black wire going up the left side to the top and taps into the main. The red wire goes over to the bottom right, then up to the top and taps into the main and then to the rest of the panel. The mains to the utility leave the bottom of the panel and that’s where the main CTs are located.

Thanks for your help!


#7

Sounds like the mains are where they were in the previous picture, so don’t worry about another one :slight_smile:

I do really think tech support needs to be involved, because the way I see it this is a computational error that may or may not be built into the software.

For example, the way mine is set up, I have the mains coming in through the main breaker, the main door feeding the panel, where it goes to my household appliances. In addition, I have my solar coming in separately through a second breaker, a side door, feeding the panel and going to my household appliances and, when in excess, back through the mains to the grid. Essentially I have two doors to get into the room that is my panel, and Sense is monitoring both doors to see who’s coming in and going out.

Yours, on the other hand, is like a church with a big atrium. Mains coming in, but solar coming in right there at the same spot through two doors on either side of the main door. where Sense is trying to monitor who’s coming in and going out at the same time. Assuming there was a small delay in when you took the pair of screenshots, here’s my math: take the solar, subtract both the mains to get 729 - which is how much your house is consuming at that very moment. Makes sense because solar is producing and mains are reversed letting the excess out. Now, take the solar again and subtract ~729 to get ~3406 (admittedly we’re off by about 120 which could be either a fluctuation in production or usage or both between 1138-39). There’s something in the way sense naturally accounts for what it puts on that main histogram page that wants to subtract your usage from your solar.

The math makes my head hurt, but I have to wonder if this may be due to how your solar is connected to the panel. I wonder if tech support will need to rewrite the calculations for your device to accommodate. Where that happens is what I’m not sure about - in the software itself or in the app :confused: I would try recalibration when the sun is out (all it really needs is >150w based on past experience), and see whether that fixes it… Or wait for more advice and input from tech support.

edit based on a competitor’s website, your setup is known as supply side solar, and at least on that platform, requires a different mechanism of calibration compared to the setup I have (load side solar): http://support.neur.io/customer/en/portal/articles/2171169-sensor-configurations-for-supply-side-solar-tie-in-setups (sorry Sense if that’s inappropriate to link). I am not sure whether Sense handles figuring this out on its own, or whether the Sense platform needs to investigate a similar approach.


#8

Just a status update. My solar is supply side (because it can generate up to 80 amps and code does not permit it through the breaker). Tech support resolved the problem (at their end) and now I am seeing the values in the directions they should be.

I don’t know how close it is to real values, that’s next on my list to figure out, using the Net meter, solar production meter and, eventually, the solar power monitoring software (which is not yet activated since they didn’t apply power to it during installation).

But I had other electrical work being performed on the circuit breaker panel (like adding a subpanel, outside outlets etc, and that hooked it up, now I just have to wait for the monitoring initial programming. At least then, I’ll have a breakdown of each panel’s power (micro-inverters), combined with the whole house monitoring of Sense.


closed #9