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Are optimizers & Charge controllers compatible?

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  • Are optimizers & Charge controllers compatible?

    Hi all
    I've been watching the sun/ shadows for a few years, as I'm getting ready to start setting up my ground mount system. I'm still weighing the options regarding the exact location and layout of the array, but it looks like 3 - 4 out of 10 panels might be shaded in the afternoon. So to keep my options open for the time being, would it be possible to put optimizers ( SMA , Tigo ) on the shaded panels? The CCs will probably be Midnight or Outback.
    Thanks in advance
    Pete


  • #2
    Originally posted by petect View Post
    Hi all
    I've been watching the sun/ shadows for a few years, as I'm getting ready to start setting up my ground mount system. I'm still weighing the options regarding the exact location and layout of the array, but it looks like 3 - 4 out of 10 panels might be shaded in the afternoon. So to keep my options open for the time being, would it be possible to put optimizers ( SMA , Tigo ) on the shaded panels? The CCs will probably be Midnight or Outback.
    Thanks in advance
    Pete
    Hello petect and welcome to Solar Panel Talk.

    I am not sure if you can mix string inverters with optimizers or micro's especially if you are looking at CC's for a battery system.

    If shading is an issue micro's seem to work best and having a ground mount grid tie system since access to that equipment should be easier then a roof top install.

    Comment


    • #3
      Originally posted by petect View Post
      Hi all
      I've been watching the sun/ shadows for a few years, as I'm getting ready to start setting up my ground mount system. I'm still weighing the options regarding the exact location and layout of the array, but it looks like 3 - 4 out of 10 panels might be shaded in the afternoon. So to keep my options open for the time being, would it be possible to put optimizers ( SMA , Tigo ) on the shaded panels? The CCs will probably be Midnight or Outback.
      Thanks in advance
      Pete
      yes you can put tigo optimizers on the string with a charge controller. You can also put them on just the shaded PV modules.
      OutBack FP1 w/ CS6P-250P http://bit.ly/1Sg5VNH

      Comment


      • #4
        Thanks guys.
        I currently have 10 identical panels that will be going up in the spring. If at a later date, I come up with a few more panels ( lets say 2 - 4) that are different from the existing panels, can I use an optimizer(s) to add them to my system? If so, how would I do that? I know I'm speculating, but I'm trying to avoid painting myself into a corner.
        Thanks again
        Pete

        Comment


        • #5
          Originally posted by petect View Post
          Thanks guys.
          I currently have 10 identical panels that will be going up in the spring. If at a later date, I come up with a few more panels ( lets say 2 - 4) that are different from the existing panels, can I use an optimizer(s) to add them to my system? If so, how would I do that? I know I'm speculating, but I'm trying to avoid painting myself into a corner.
          Thanks again
          Pete
          If the new panels produce more current for a given amount of sunlight than the existing ones, then they will work just like the existing ones. You won't get the benefit of the higher amount of power the new ones could produce, but at least they won't bog down the rest of your string.

          If they produce less current, though, it would be counterproductive to add them because they would limit the current flow through the entire string of panels.

          The Tigo optimizers work by allowing a lower-producing panel to increase its current flow to match that of the overall string, at the cost of lower voltage across the panel. It is essentially a buck converter, converting (1) a voltage not much lower than full-sun Vmp but at low current due to shading into (2) significantly lower voltage at full-sun current flow. Thus the shaded panel can still offer its measly contribution to the overall string voltage while not constricting current flow through the string.

          Bear in mind, though, that a shaded panel under blue sky will produce less than 5% the power of a panel in full sun. Is that really worth it? The bypass diodes in your panels will just reroute the currrent past the shaded panel (or part of it) and you won't really miss the 5-10% they would provide with an optimizer.

          Where the optimizer makes sense is if you have soft shading going on from faraway trees. Because the sun is not a point source (it subtends 0.5 degrees of arc), the shade from a few branches a hundred feet away may knock several panels down by half. It could be useful to get that half-power from a good chunk of your array.

          I'm dealing with this myself in the low sun angles of a winter at 48 degrees latitude, even after some chainsaw work. A single lousy pine top a hundred feet up and two hundred feet away, with its straggly branches shadowing several panels just a little bit, can significantly mess things up with a string inverter and no optimizers. So I'm actually considering them despite what I wrote above.

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          • #6
            Hey BWEE Thanks VERY much. Your reply was very helpful!

            Pete

            Comment


            • #7
              Originally posted by petect View Post
              Hey BWEE Thanks VERY much. Your reply was very helpful!

              Pete
              You're welcome! I've benefited a lot from reading contributions from the wise old hands here and am happy to give a little bit back when I can. It's a great forum.

              Comment

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