Negative Watts

My experience with the negative power was never adequately resolved and the support experience was exactly the same as yours!
I do have the solar plugged in and it shows a negative value everyday after the sun goes down, because I have about 150W of draw between my solar production and the Sense solat CTs.
That is OK, it’s the negative power on the Sense Mains power that never got resolved. Support had me reset, recalibrate half dozen times and they fiddled things on their end to no avail. Finally stopped pestering them, figured they had more important problems! The turnaround time was the same as yours and the support staff appeared to be working off scripts and answers appeared to be mostly cut and paste.
My solar production appears correct.
Very few devices detected and my Sense module appears to be a slow learner as it is stuck on the Garage Door and Motor for two months.

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I’m still communicating with the people at SENSE, and they are trying to
help me! They agreed to a phone call with my electrician!

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I’m experiencing the exact same problem as described by the OP.
Has this been resolved?
I’ve sent two emails to Sense but I have received no response other than the canned email that says they’ll get back to me “as soon as we can” (which seems to be never).

Looks like they need to hire more people.

Ok, I solved the problem.
All I needed to do was to change the direction of both clamps. The manual says the direction does not matter as long as both clamps point to the same direction. That happens to be incorrect. It matters very much. So, if your Sense is reading negative power, change the orientation of both clamps and that should fix the problem.

Not only the orientation of the clamps matter, but also it’s important to re-install the clamps on the same phase has they were installed before. Not doing so causes the devices that your Sense have discovered before not being recognized again (it has to re-learn them). The good news is that there are only four possible configurations: orientation of the clamps (which go in pairs always) and attachment of the clamps to input lines (two phases that comes to your house). Try all four combinations if you are not sure until:
a) measured power is non-negative
b) your devices show up correctly in the timeline as you turn them on and off

Hope this helps someone.

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The manual must have changed. When I installed in my Sense in 2016, the CTs had to be oriented very specifically with respect to the flow of current. What didn’t matter was which leg each CT was clamped to.

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You are right. The manual has changed. When I installed Sense in 2017, it also specified direction in a certain way

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I had the same situation (negative watts after the electrician modified the panel for a solar install after Sense had been running for months) and found a way to fix it.

Turned out to be that the electrician had to unplug the Sense power wires from the breaker they were in. He reconnected them to the breaker afterwards, but inverted the phase (red in black’s previous spot and vice vera). I switched them and problem solved. Did not have to do a reset.

Now I get negative watts only when solar production exceeds my consumption because this is a grid tie-in. (I am still waiting for my Solar CTs to arrive).

Hope this helps.

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Did you eventually hear from Support? We are only active Monday through Friday, so that can cause some delays.

And glad you got it fixed! The manual has changed re: sensor orientation because it is now possible for us to fix most issues that arise from that remotely.

Yes, I heard from support after I opened a second ticket and after I fixed the problem by changing the orientation.

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I was having the same problem (negative wattage readings) after my initial install. After reading through these comments, I flipped the current sensors/clamps (from Sense label facing up originally to Sense label facing down now) and that solved my problem. Positive watts now.

The instructions state “The direction of the sensors does not matter, as long as they are the same” but that is not correct in my case…

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Nor was it in my case 18 months back. Advised tech support about the issue then. Appears nothing was done.

Thanks for bringing this up @kushner.jeff and @1agkirk2 -

Best thing to do is make sure the stickers on your current transformers are both facing in the same direction during the initial installation, whether that is up or down matters much less. Either way, your monitor should automatically correct for the position of the current transformers after the installation and during the signal check process, even if one sticker is facing up, the other facing down or something like that. That does take 24-48 hours as it runs through the process, but one of the biggest problems our support team runs into is customers flipping their current sensors after that signal check process goes through, or while it’s trying to calibrate.

Should anyone run into negative wattage readings a day or two after installation, please reach out to the support team so they can help get things straightened out, and don’t flip your CTs while the signal check process is going on. In the meantime, we’ll try and come up with ways to make this clearer in the installation guide and video, so thank you for your feedback!

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@BradAtSense. So if I installed Sense yesterday and got the negative wattage readings and flipped them today resulting in positive readings but the signal check was not complete, what should I do now?

Hold tight for the moment, as signal check may still be able to catch their current state. I might submit a support ticket proactively and let them know so they can keep an eye on the signal check process and make sure it all goes according to plan!

Congratulations on getting your Sense installed, and welcome to the community!

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I had this issue on one of the poles. I did indeed have one clamp facing one way and the other clamp facing the other direction. Taking the clamp off and changing the orientation fixed my negative watts issue.

Thx

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Welcome to the community @lionel
Glad you got it straightened out. Hopefully it wasn’t one ther long with the wrong orientation as that can affect the data and influence detections.
Support can also correct things like this on their end when this has happened.

I was seeing a dozen or so negative watts on one of the mains shortly after installing and watching the Sense Monitor. After reading this exchange the thought occurred to me that I might have clamped to the neutral main rather than the second power main. I checked and sure enough, I’d made just that error. I powered of the Sense monitor, clamped to the correct main and now have positive watts on both lines!

Ok so I may have stumbled into this scenario as a new user tonight. Came here after the fact and now it all makes sense.
Sense should take note of this because I’d bet this happens more often than not. I installed my sense this afternoon with zero issues. Watched stats for a couple hours and ran to Lowe’s to get a couple more breakers to replace some larger (physically) than normal breakers that I hadn’t touched during install. During the replacement I had to move some breakers around because my panel only allows tandem breakers in certain spots. At one point I needed to move the two pole breaker feeding the sense unit up one slot. The wires remained on the breaker during the quick move which meant they actually switched hots they had been fed from on the panel.

Powered everything back on and had negative watts showing in the about menu and zero watts on the now screen. I opened the panel and switched the two ct’s between the hots to rectify the problem.

Note the ct’s weren’t touched since install but the breaker feeding the sense unit was to facilitate the breaker moves. I could see this happening with a solar addition or frankly many adds in a tight panel. So if you have work done and you know a fact the ct’s didn’t move, I’d bet your breaker positions or leads for the sense got swapped.

I didn’t have any devices detected yet so I didn’t lose anything. I could have simply swapped the hots in the load side of the breaker feeding the sense but being a new install the ct’s were quicker.

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