Solar is driving my usage negative

I’ve had Sense for over 2 years and solar for 2. I haven’t touched the installation since my solar was added. Starting last week I noticed that as my solar generation comes up in the morning my usage goes down and becomes negative. The first picture is from Tuesday When everything was normal. The second is from Thursday showing negative usage. There is no history available for Wednesday. I suspect there was some sort of system outage or firmware update that has messed up the calculations. I tried a reboot of the Sense monitor today but when it came back online it was showing the same negative usage. Anyone else experiencing anything similar? Any suggestions?

Thanks.



WHen you send these pictures in an email to support they will fix it.
This is a problem that pops up way more often then I think it should.
I have explained in another thread the difference between supply side hookup and load side hookup of solar.
The fact that it worked for 2 years without a hitch and suddenly it switched from one setting to the other is something Sense should look in to.
This happened to my system and the system of one of my customers where I installed sense multiple times.
And basically it shouldn’t switch.
Maybe someone from Sense can check this out with the techies/programmers?

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Interesting human-interface logic here to potentially avoid configuration and support issues:

  • Sense (account/monitor) clocks stable configuration time. i.e. “no changes made”, or something like that.
  • Mains or Solar or DCMs go significantly negative.
  • Send alert to user.
    “Did you change something?”
    YES ==> “Maybe you did something wrong, wanna check?”
    NO ==> “OK, maybe something went wrong, let’s check”

This can be tricky logic at scale I suppose but then so is juggling a slew of support requests if something goes awry.

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I have the same problem. Well mine has not worked right since it was installed. (I’ve been in touch with support but it’s been a frustrating experience that never solves the problem.) My problem shows up two different ways that switch from time to time - and we are not in our house right now so our usage is very consistent (except when I bring our car to the house charge): As shown in the screenshot, sometime the usage tracks solar generation exactly, minus about 300w. And then some days the solar generation drives our usage negative. Is something hooked up incorrectly? Would love some help. Been over a month and support just isn’t cutting it…

@rod.tiedemann, @jh9856,

My take is that your Senses have become mis-configured (or in @jh9856 's case, not auto-configured correctly at the start). As @dannyterhaar partially suggests, there are a lot of permutations of:

  • CT orientation (16 possible combinations with Solar - 4 CTs)
  • CT relationships (which CT goes with which measured voltage leg) - mains and solar each have 2 possibilities.
  • supply side hookup vs load side hookup (2 possibilities)

The Sense calibration / solar setup step attempts to get this right and most of the time succeeds. If it doesn’t you see results like you are seeing and support@sense.com should be able to help.

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I contacted support and they diagnosed the problem as a loss of connection to one of the solar CTs. They sent a short extension cable, that includes slightly larger pins and a bit of protective grease, to be installed between the existing CT cable and the Sense unit. I finally got around to installing it today. Worked like a charm.

Thanks

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