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  • Enphase equipment readings and accuracy

    Hello all, I'm a new member an had a 10kw solar system installed on my roof last October. The system has a enphase combiner box that measures my solar production to a meter in my garage. My new netmeter outside the garage seems to be reading correctly but my enphase consumption readings on my phone from my enphase application seem to be way off and do not seem to conform to the measured readings netmeter. It seems to me that consumption values enflated when I larger solar production values.

    I have a separate energy monitoring system on my service from powerhouse dynamics that monitors the energy usage on my mains and ever breaker in my service panel. That system readings states my consumption is around 25-35kwh a day. The enphase consumption reading from my solar system place my consumption around 50kwh a day.
    The days I'm not producing a lot of solar power the consumption readings are closer but my solar consumption reading are always about 10 percent higher. Has anyone else noticed similar results? If my netmeter reading seem to conform to the usage on my more accurate whole house energy monitor should I even care if the enphase consumption readings are 10-50 percent higher?
    I would like to post some examples but can't seem to figure out how to post in the photo's yet. I tried to contact my solar install about the accuracy but haven't heard anything back.
    im sure they get bothered by this sort of thing all the time.

  • #2
    Sounds similar to the situation of a person with two watches never knowing the correct time. I'd be interested in hearing what the installer has to say.

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    • #3
      Ya, Enphase. Lets compromise the inherent super reliability of a PV panel by mating it with something much less reliable so that you can have module level visibility.
      BSEE, R11, NABCEP, Chevy BoltEV, >2000kW installed

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      • #4
        Originally posted by solarix View Post
        Ya, Enphase. Lets compromise the inherent super reliability of a PV panel by mating it with something much less reliable so that you can have module level visibility.
        I've wondered for some time now how many folks actually pay much attention to their system's monitoring capabilities. Anecdotally, of the dozen or so systems in my HOA that I monitor on a semi-informal basis with 7 string (and 3 SolarEdge) and 5 micro systems, no one ever looks at (and for the most part probably wouldn't be aware if I hadn't informed them) their panel or system monitoring.

        Seems to me like a lot of added complexity for claimed and paid for but unused capability.

        As for restored shade performance, I'll concede that some is possible and likely as I have no numbers to back up my opinion as to their worth to improve annual system output lost from shade, but I'm pretty sure micros or optimizers won't restore performance that wasn't present in the first place - that is - lost to shade.

        My educated guess is that a lot of peddlers B.S. the solar ignorant and sell equipment into very inappropriate shade applications with tales of micros/optimizers turning what are actually poor applications into good applications. I might be a skeptic and a cynic, but I've seen too much of it, including from the other side as a commissioned salesperson.

        But back on topic, I'll still be interested in reading what the installer finds/suggests.
        Last edited by J.P.M.; 03-29-2019, 11:25 AM.

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        • #5
          Attached are some examples: The daily kWh usage verses enphase usage examples. I've decided to add another energy monitor to the enphase combiner box with their ct's. The measure the multiple in-coming solar leads. I'll tie into the output solar leads with a single set of 50 amp on each of the larger wires. The combine box already has a 10 amp 110vac pug for accessories for the combiner box available. Then, I'll be able to talk apples to apples and verify my solar generation.

          if my consumption ct's Are this far off, I'm starting to wonder about my solar generation ct's.

          if it was 10% percent I probably wouldn't bother, but 40-50%? There is no call for that.

          Attached Files

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          • #6
            Originally posted by Wavelet8 View Post
            Attached are some examples: The daily kWh usage verses enphase usage examples. I've decided to add another energy monitor to the enphase combiner box with their ct's. The measure the multiple in-coming solar leads. I'll tie into the output solar leads with a single set of 50 amp on each of the larger wires. The combine box already has a 10 amp 110vac pug for accessories for the combiner box available. Then, I'll be able to talk apples to apples and verify my solar generation.

            if my consumption ct's Are this far off, I'm starting to wonder about my solar generation ct's.

            if it was 10% percent I probably wouldn't bother, but 40-50%? There is no call for that.
            I would start with looking at what the numbers being reported actually represent.
            How does Enphase know anything about your consumption?
            Is it communicating with your house meter?
            I would only expect Enphase to know production - because it can talk to each microinverter and the inverter can report how much it produced.
            If it's reporting more than that it has to get it's information from somewhere - where is it getting that info? Is that info accurate? Or it doing something like counting number of times a disk in the meter completes a revolution? But that disk could be going forward or backward, so it mis-counts.

            You could turn off all the breakers to your house except the solar for an hour or two tomorrow - and see if you have only production and zero consumption during that time.
            (you should - if you don't probably something's being reported as consumption instead of production.)

            BTW - unless enphase says their metering is "revenue grade" or is speced to be "within 1%" it can be off by 5% (and probably is).
            My Solaredge system reports 2-5% more than if I measure what's produced with the POCO meter or with TED5000 system. (The POCO meter and TED agree within 1% - which is good because they're supposed to have an error of less than 1%. The Solaredge system specs I think say +/- 5% )

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            • #7
              Does your Enphase monitoring box have CT Clamps or is it the typical Envoy?

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              • #8
                Their is a single ct for one phase in the combiner box. See attached photo and diagram.
                I just installed the other energy monitor today and ct for each of the two phases. Trying to calibrate again now because I had direction between produce and consumption in correct. Might not make it because sun is going down and the kids in the bounce house takes priority.

                I'm still waiting on information from the installer. The sales guy thought their was an additional set of CT's for consumption but I'll wait for someone more technical.

                For some reason, my response will not let me attach the photo?

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                • #9
                  Photo
                  Attached Files

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                  • #10
                    Originally posted by Wavelet8 View Post
                    Photo
                    That one ct is only measuring production. This is a revenue meter. How is enphase measuring consumption?
                    OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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                    • #11
                      I'm waiting for that information from the installer.

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                      • #12
                        Another photo with new energy monitor installed.
                        Attached Files

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                        • #13
                          Originally posted by Wavelet8 View Post
                          Attached are some examples: The daily kWh usage verses enphase usage examples. I've decided to add another energy monitor to the enphase combiner box with their ct's. The measure the multiple in-coming solar leads. I'll tie into the output solar leads with a single set of 50 amp on each of the larger wires. The combine box already has a 10 amp 110vac pug for accessories for the combiner box available. Then, I'll be able to talk apples to apples and verify my solar generation.

                          if my consumption ct's Are this far off, I'm starting to wonder about my solar generation ct's.

                          if it was 10% percent I probably wouldn't bother, but 40-50%? There is no call for that.
                          These photos clearly show the enohase consumotion miss configured in one way or another. The cinsumotion ( orange ) is mirroring the producton ... it should mirror the grid imoort at night and stay roughly the same during production...
                          OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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                          • #14
                            True, the combiner box only has a single ct that monitors solar production. The combiner box outputs to a solar production meter in the garage then outputs to the output side of my netmeter outside the garage. So, if any ct's Exist for the enphase system the have to be in my netmeter outside but if consumption system exists it's communicating over the power lines. I find this unlikely but not impossible. That why i'm Asking how is the consumption values generated for the enphase system. My netmeter reading doesn't correspond to enphase consumption reading. It's probably some strange estimation but I would like to know.

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                            • #15
                              Originally posted by Wavelet8 View Post
                              True, the combiner box only has a single ct that monitors solar production. The combiner box outputs to a solar production meter in the garage then outputs to the output side of my netmeter outside the garage. So, if any ct's Exist for the enphase system the have to be in my netmeter outside but if consumption system exists it's communicating over the power lines. I find this unlikely but not impossible. That why i'm Asking how is the consumption values generated for the enphase system. My netmeter reading doesn't correspond to enphase consumption reading. It's probably some strange estimation but I would like to know.
                              Enphase cleRly has something measuring your net someplace or it would have zero for all night long. They just have something configured wrong and there are several ways to do it wrong and get this result.
                              The ince CT can only ever monitor production which is not needed unless you need revenu grade production meter for SRECs as the micro invertes each give production. You can get consumption by adding net and producton ( production is usually negative) .
                              OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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