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adding panels: two separate inverters or one new big inverter

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  • #16
    Originally posted by ButchDeal

    As well as cost, tax, and points of failure...
    Everyone has a different goal to make sure their investment provides them something even partially.

    IMO a belt and suspenders to keep my pants up is overkill.

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    • #17
      Originally posted by SunEagle View Post

      Everyone has a different goal to make sure their investment provides them something even partially.

      IMO a belt and suspenders to keep my pants up is overkill.
      When used simultaneously, some call one or the other of those a backup system.

      Two inverters when one will do seems to be getting close(r) in some (but not all) ways to some of the selling point of micros - more flexibility.

      In a way, it comes down to the designer's philosophy of how to design equipment or what's fit for purpose in an application.

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      • #18
        Originally posted by J.P.M. View Post

        When used simultaneously, some call one or the other of those a backup system.

        Two inverters when one will do seems to be getting close(r) in some (but not all) ways to some of the selling point of micros - more flexibility.

        In a way, it comes down to the designer's philosophy of how to design equipment or what's fit for purpose in an application.
        yes clearly DanS26 thinks that two inverters when one will do is a backup solution. It is not. Two inverters where one is standby until the other fails is a backup solution.
        There really is no need as the inverters are doing production, and the grid is the main power source. IF the inverter fails, the homeowner is not out of power just a few days production till they get the product fixed.
        With two inverters as DanS26 suggests, there is still a loss of production till the inverter is fixed, but only half of the production. The down side is there the likely hood of failure is increased, as well as costs.
        The result of the failure is reduced; half production for a few days vs full production for a few days.
        However the production for a few days is of minimal value and the difference of half production to full production for a few days even a few weeks is very minimal considering the total life of the systems. In fact the single inverter would enjoy higher production (already mentioned in my earlier post) than two individual inverters.

        It is a false since of security for a non-problem, or in other words a painful cure for a minor and unlikely issue.
        OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

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        • #19
          Originally posted by matrose View Post
          I have an existing PV system of 15 Canadian Solar 260 panels together with SolarEdge P300 Inverters and a Solaredge 3800 inverter. I want to add 11 Sunpower E19 320 watt panels with Solaredge P400 optimizers. I could do that buy adding a separate inverter the smallest 3KW Solaredge inverter or buy buying one big new inverter, maybe the 6 kw one or 7.8 KW one and run all panels on one inverter. The new system will get significant shading for some panels at all time of the day, since the panels are oriented south, west, east and two north. So I thought all on one might be better, because it would make it easier to reach the minimum voltage for the inverter to kick in. Does it matter which way I go? Two separate inverters or one unified one? There would be only two strings altogether: one from the existing system and one from the new system . Thanks for any suggestions ! Matthias
          In your application you will likely benefit from several different MPPT channels to handle several different strings.

          For example, if you went with an SMA 7.7 you'd get three strings; you could dedicate these to west, east and south strings (provided each string was long enough to meet MPPT range requirements of course.) That would leave you with two panels on the north. Not sure why you would put two panels on the north side, but microinverters might be a better choice there. You might even be able to live with a single microinverter since you'll never be getting full sun, and so can downrate significantly.

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          • #20
            Originally posted by ButchDeal View Post

            yes clearly DanS26 thinks that two inverters when one will do is a backup solution. It is not. Two inverters where one is standby until the other fails is a backup solution.
            There really is no need as the inverters are doing production, and the grid is the main power source. IF the inverter fails, the homeowner is not out of power just a few days production till they get the product fixed.
            With two inverters as DanS26 suggests, there is still a loss of production till the inverter is fixed, but only half of the production. The down side is there the likely hood of failure is increased, as well as costs.
            The result of the failure is reduced; half production for a few days vs full production for a few days.
            However the production for a few days is of minimal value and the difference of half production to full production for a few days even a few weeks is very minimal considering the total life of the systems. In fact the single inverter would enjoy higher production (already mentioned in my earlier post) than two individual inverters.

            It is a false since of security for a non-problem, or in other words a painful cure for a minor and unlikely issue.
            Butch...all your points are well taken except one.....the assumption that any problem in the array or inverter can be fixed in a few days. We have been on this site long enough to witness delays of days, weeks or even months before lost production is noticed or restored.

            Comment


            • #21
              Originally posted by DanS26 View Post

              Butch...all your points are well taken except one.....the assumption that any problem in the array or inverter can be fixed in a few days. We have been on this site long enough to witness delays of days, weeks or even months before lost production is noticed or restored.
              As stated, it is SolarEdge monitoring which can easily be set up to send alerts on any problem. I monitor a heck of a lot of them and you can find the problems quickly and easily. Have had very few inverter outages, some inverters that were replaced but were functioning just not taking updates, Allmost all were quickly after turn on.
              OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

              Comment


              • #22
                Originally posted by jflorey2 View Post
                In your application you will likely benefit from several different MPPT channels to handle several different strings.

                For example, if you went with an SMA 7.7 you'd get three strings; you could dedicate these to west, east and south strings (provided each string was long enough to meet MPPT range requirements of course.) That would leave you with two panels on the north. Not sure why you would put two panels on the north side, but microinverters might be a better choice there. You might even be able to live with a single microinverter since you'll never be getting full sun, and so can downrate significantly.
                OP has SolarEdge which has one MPPT per PV module....
                OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

                Comment

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