Electric Bill Question

Thanks. By the way, here is a scatter plot of one week. Looks crazy.

Very interesting… If I add the unity line (in red), you have a bunch of hours that are nearly dead on accurate, and a bunch of hours when Sense is far below your utility. The trick is to figure out if there is any pattern that kind of lines up with the accurate hours, so coloring your dots by hour of the day might reveal something. I would also look at the Power Meter for the hours with the biggest kWh differences (orange). If I were to guess, you are either having an issue with Sense reading one of your two panels, or you have an extra panel. Your results are accurate when the problem panel has very little power flowing through it. Or you might be seeing some partial data dropouts that would likely show up in the Power Meter for the points in orange.

I struggle with this as well. According to sense my solar production from utility is lower than Sense which is lower than Enphase. I am still identifying phantom loads then will focus on accuracy. I really like the scatter plot…

Maybe one of the four CTs is bad, have you left one branch of the 400A service off for a couple hours? Maybe that will identify the issue.

I’m upgrading to 400A service soon, how do you have yours wired? Can you post pictures or DM?

I’m interested in what you discover with the accuracy…

Here are several photos. How can you check if any CT is bad. Are you saying to flip all the breakers in one panel and then check Sense vs. my utility?. I’m tempted to get another Sense and CT’s and put them on the meters outside where the utility meter is. Everything would be enclosed except the antenna. Do you know if Sense can be installed outdoors in the electrical box (cold/heat) and is it ok for the antenna to get wet during rain/snow? I have a good wifi signal outside. Maybe that is a better question for Sense support. Thanks for your input.

You could take the aux CT’s and put them on the same conductors as the main CT’s and make sure they are metering the same.

Per the sense install guide and also FAQ

Outdoor installations
To install Sense outdoors, it must be enclosed inside an appropriate NEMA-rated enclosure, and adequately protected from the elements. Sense is compatible only in the following environmental conditions:

Relative humidity <90%; IPX0 rating, no water ingress
Temperature: 32-154ºF (0-68ºC)
Elevation < 6562’ (2,000m)

If you search the forums, I think you will find people who have their Sense installed outdoors and have had it survive conditions outside of the temperature range, but the official is 32-154°F

If you can move your Sense to your meter, you will certainly have the highest chance of capturing all of your consumption.

Check with your utility to make sure you can open the meter base to install the sensors. Most do not allow cutting the meter seal. Also you probably need to have the sense voltage input on a protected circuit.

If you were allowed, how far is the meter base from the panels? You could keep the sense in the panel and just run your ct circuits outside if you have enough cable.

So just to make sure I understand. If I wanted to purchase another Sense system and try it outdoors (I understand the risks due to weather), I would then have 2 sense systems looking at my house. I would have two accounts I could look at and the new Sense would begin discovering devices. I could then check both of them against the utility bill and see if one of them is more accurate than the other (or if I am losing electricity from the main feed to my basement panels. Have I got that right?

I would put aux CT’s and mains together just to test the CT’s first before buying another unit. Plus as I mentioned above you will need to check with the utility to make sure you can do this.

Best I can tell the total usage sums up the two mains. I don’t think I can see their separate kWh values. I may be way out of my league here

While I was only commenting on the tech specs of the unit, yes, what you are proposing would work as its just now two totally standalone Sense’s assuming that you are able to install it with the questions that @phil435 has raised

I guess I would ask you why you would buy another Sense vs just moving your existing Sense to the outdoor panel (or if indoor/outdoor are near each other and you have space in the conduit, just move the CT’s with extensions and leave the Sense where it is)

Its a lot of money just to “test” if your current unit is working correctly. There is no real benefit to having both. As you know, they are on two separate accounts, so there is no integration between them. You have to log out / log back in to view the data. If one detects a device, it doesn’t mean that the other necessarily will.

With the exception of data loss due to internet outages, my Sense has been well within the 1% accuracy rating for 4 years. Personally I would spend a little more time tracing wires / troubleshooting with Sense support and just flipping breakers to see if the problem is elsewhere before dropping another $250.

Can you take photos of your outdoor panel? There is not a main breaker in either of the panels you showed photos of, so the main house disconnect is presumably outside. It is not uncommon for the panel that houses this main disconnect to also have a few slots for breakers, so this may well be your missing consumption.

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Sorry I probably wasn’t clear. To test your CT’s, physically move the aux/solar CT’s with the mains in box 1. Both should be showing close to the same values unless you have a ct issue.

You could have a slight discrepancy at first if CT’s are not matched to the same leg. I don’t think the CT’s have any markings on them showing the relationship to the voltage inputs.

I agree with @ben. Take some pics of your meterbase so that we can see the entire meter base.

I have similar accuracy as @ben. I am less than .005 percent off of the utility values. Keep in mind that some hourly data from the utility could be “estimated” if they miss an interval but I don’t think this is what your seeing. I think you did correct by looking at the total usage on the bill which should be accurate and not estimated.

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Thanks for the photos. I’m with @ben. Pictures of your meter box would be useful. If you have breakers in there, that’s your missing load. One more thoughts on sources for missing power - your extension cable looks like it is unhooked in one of the two photos at the bottom. Make sure that connection is seated well.

Thanks all! I think that may be the problem. I’ve attached a few photos. Please give me your thoughts. Is it typical that those breakers would go to the outside condensing units? If this is the cause of the missing power then the only option is mounting the sense outside in the breaker panels right? Thanks again for everyones help!

Great ! Sense is really, truly a voyage of home discovery :wink:

What kind of 240V devices or sub panels do those dual 20, 30 and 35 supply - AC condensers ? Betting those were all off when your Sense hourly usage results matched up with your utility. I guess you need to put your Sense CTs out in the meter boxes. If possible, you might want to put one set on the single pre-meter mains and use the aux port for DCM of a couple of those 240V loads.

It looks like you have three circuits on the mains outside. The one on the right has two carflex’s leaving it and the one on the left has one.

I assume each box comes through the house on the back of the main panels? If so, then why not leave your sense inside and run the ct cables to the outside? You can get in the boxes to the left and right of the meters without checking with the utility.

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I have 3 condensing units very close to the main feed on the house. Best I can tell is they go straight to the condensing units. Since I have split service I am using all the CT’s available with Sense correct? If so, then if I moved sense outside would I be able to capture all the power? It looks to me that the breakers never go into the house. Do you know if the utility would allow CT’s inside their meter box? I could call them. Right now it is nice for a few days and I may just shut those three breakers off and see what it looks like over the next day or so.

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If you put the CT’s on the mains in the box to the left and right of the meterbase then you will catch everything. You don’t need to contact the utility for that.

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Take the cover off of one on the boxes to the left or right and see if you have a conduit going into the back of the wall. These should be going to your main panels inside.