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Wattnode with 2 HD inverters

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  • Wattnode with 2 HD inverters

    I acquired two wattnode meters and am in process of installing. I noticed that on the solaredge manual for these, they mention using a communication gateway if connecting to two inverters.

    Is this absolutely required? I don't care if the second inverter is unable to display on its screen the meter's output. I just want this data (E + I, Cons.) to display on the Web portal and mobile app.
    https://pvoutput.org/list.jsp?sid=54099

  • #2
    Not an authority on the product and just making an educated guess, but any Inverters I have seen used in cascade need to talk so they can sync up with a timing signal.
    MSEE, PE

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    • #3
      How are you configuring the wattnode? As a revenue grade meter or consumption meter? If a consumption meter then you only need one of them. If revenue grade you could also do it with one if you set it up right.

      You will likely need the gateway to get the additional serial port as the inverters are likely connected using the one port.
      OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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      • #4
        Originally posted by ButchDeal View Post
        How are you configuring the wattnode? As a revenue grade meter or consumption meter? If a consumption meter then you only need one of them. If revenue grade you could also do it with one if you set it up right.

        You will likely need the gateway to get the additional serial port as the inverters are likely connected using the one port.
        I have two WNC-3Y-208-MB meters. One is between grid and house+inverters. The other is between house and grid+inverters. So I will have an export/import meter and a self-consumption meter.

        It appears that the inverter supports two meters connected on a single RS-485 port, and it also appears it has two RS-485 ports (though, again, only need one). Both of my inverters are connected via ethernet, so both RS-485s are available.

        I'm assuming that just connecting both meters to one inverter, and configuring that one inverter for both meters, will suffice. Can't hurt to just try...
        https://pvoutput.org/list.jsp?sid=54099

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        • #5
          Originally posted by NukeEngineer View Post

          I have two WNC-3Y-208-MB meters. One is between grid and house+inverters.
          This meter is measuring NET and can be used to calculate consumption by subtracting generation.

          Originally posted by NukeEngineer View Post
          The other is between house and grid+inverters.
          So you have a line side tap for your inverter. This meter is measuring consumption and is really not needed.

          Originally posted by NukeEngineer View Post
          So I will have an export/import meter and a self-consumption meter.
          You have a meter measuring NET and one measuring consumption but consumption can mathematically be calculated by subtracting generation from NET.

          Originally posted by NukeEngineer View Post
          It appears that the inverter supports two meters connected on a single RS-485 port, and it also appears it has two RS-485 ports (though, again, only need one). Both of my inverters are connected via ethernet, so both RS-485s are available.

          I'm assuming that just connecting both meters to one inverter, and configuring that one inverter for both meters, will suffice. Can't hurt to just try...
          generally your inverters would be connected to each other on one port and the other port would be free as long as you set the address of the inverters correctly.
          you really only need one wattnode though.
          Last edited by ButchDeal; 06-24-2018, 11:19 PM.
          OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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          • #6
            Understood that only one wattnode would have been fine, but a) they were cheap, and b) solaredge implies that the power/energy measurements by the inverters themselves is "not so great", much more accurate with 0.5% wattnode.

            With the configuration I have, I'm getting exactly the data I'm most interested in, what the house is using and what the grid is getting/giving, at 0.5% accuracy.
            https://pvoutput.org/list.jsp?sid=54099

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            • #7
              Originally posted by NukeEngineer View Post
              Understood that only one wattnode would have been fine, but a) they were cheap, and b) solaredge implies that the power/energy measurements by the inverters themselves is "not so great", much more accurate with 0.5% wattnode.

              With the configuration I have, I'm getting exactly the data I'm most interested in, what the house is using and what the grid is getting/giving, at 0.5% accuracy.
              It is more accurate if and only if you use a revenue grade wattnode.
              OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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              • #8
                Originally posted by ButchDeal View Post

                It is more accurate if and only if you use a revenue grade wattnode.
                The RWNC and WNC are both 0.5% accuracy. The RWNC has a CT rating register locked, and meets ANSI C12.1, which probably adds temperature and humidity variance requirements. But I couldn't get RWNC's for $40 each
                https://pvoutput.org/list.jsp?sid=54099

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                • #9
                  Just to close out this question, the communication gateway wasn't needed (for HD inverters anyway). Just connected both meters to one inverter, and it's reporting in the portal for the whole site.
                  https://pvoutput.org/list.jsp?sid=54099

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