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Solaredge inverter sizing?

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  • #16
    Originally posted by Lews411 View Post
    He said the inverters work better and produce more when over driven. If your average high temp is below 76 degree you can over power by as much as 35%
    That jives with their technical paper on the subject, but still doesn't explain why (neither does the paper).

    I'm also a little suspicious about the average temp thing. I mean, where I live the historical average year round is 73. But, it's in the 50's in January & easily 110 in July. Why would the average matter? Seems an overdriven inverter would not be happy in the summer here?

    Pretty confusing, but I've heard the overrating thing from 3 different installers now.
    6k LG 300, 16S, 2E, 2W, Solaredge P400s and SE5000

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    • #17
      Originally posted by Bikerscum View Post
      That jives with their technical paper on the subject, but still doesn't explain why (neither does the paper).

      I'm also a little suspicious about the average temp thing. I mean, where I live the historical average year round is 73. But, it's in the 50's in January & easily 110 in July. Why would the average matter? Seems an overdriven inverter would not be happy in the summer here?

      Pretty confusing, but I've heard the overrating thing from 3 different installers now.
      FWIW: On sunny days, with low wind velocity, my ambient roof temp. runs about 20 deg. F. higher than the air temp. on the back porch. Again, depending on wind velocity, direction and solar irradiance, the panel temps run ~~ 40 to 50 deg. F. or so hotter than the roof ambient air temp. If the micros are attached to the panels, my guess is they'll run somewhere between the roof ambient air temp. and the panel temp. So, in my case, if 70 deg. air-->> ~90 deg. roof air -->> ~ 140 deg. panel temp. -->> micro temp ?? -->> (90+140)/2 = 115 deg. F ?? Maybe a bit less on a SWAG.

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      • #18
        Ok, so here's my latest 100% mostly firm decision...

        Best case scenario, I'll have 18 panels facing south, 2 east, and 2 west. The total system size is 6.05k with Solaredge optimizers. The Solaredge 5k inverter is rated @5450 max @240v. Solaredge recommends (and will warranty) you over driving it up to 125%, or 6.25k. (Interesting to note here that the 6k model is the ONLY one in the Solaredge lineup that is NOT rated for more max power than it's label rating.)

        The theory I keep hearing is that the smaller, overdriven inverter will startup sooner, making more power in low light conditions. Given that 4 of my panels will point east/west, I think this will work for me. In any case, I can't see my system putting out over 5450 and getting clipped.

        I plan on spending the $303 for a 20 year warranty regardless of which size I get, so lifespan isn't an issue.


        Yes?

        Please?
        6k LG 300, 16S, 2E, 2W, Solaredge P400s and SE5000

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        • #19
          Originally posted by Bikerscum View Post
          The theory I keep hearing is that the smaller, overdriven inverter will startup sooner, making more power in low light conditions. The Easter Bunny and the Tooth Fairy are equally true.

          I plan on spending the $303 for a 20 year warranty regardless of which size I get, so lifespan isn't an issue. Probably a good idea - is it a 3rd party insurance type of warranty? The party themselves may well not be around.

          Comments in bold within the text
          [SIGPIC][/SIGPIC]

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          • #20
            Originally posted by Bikerscum View Post
            Ok, so here's my latest 100% mostly firm decision...
            Best case scenario, I'll have 18 panels facing south, 2 east, and 2 west. The total system size is 6.05k with Solaredge optimizers. The Solaredge 5k inverter is rated @5450 max @240v. Solaredge recommends (and will warranty) you over driving it up to 125%, or 6.25k. (Interesting to note here that the 6k model is the ONLY one in the Solaredge lineup that is NOT rated for more max power than it's label rating.)

            The theory I keep hearing is that the smaller, overdriven inverter will startup sooner, making more power in low light conditions. Given that 4 of my panels will point east/west, I think this will work for me. In any case, I can't see my system putting out over 5450 and getting clipped.
            I can't see your exact panel orientation, but here is how it would work here. Your 18 panels
            are rated 4950W. If the 2 east facing panels were at 100% and 550W, I'd expect 10% of that
            from the west facing 2 panels, 55W. Total is 5555W, with 97% inverter & DC wiring efficiency,
            this amounts to 5388W output. In reality the E, S, and W facing will never be at peak anywhere
            near the same time, so you probably will never be near clipping.

            The early startup is bunk. My inverters start up as soon as it is light, but they don't put out
            significant power for an hour or so. Same in reverse at sunset. Bruce Roe

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            • #21
              Originally posted by bcroe View Post
              The early startup is bunk. My inverters start up as soon as it is light, but they don't put out significant power for an hour or so. Same in reverse at sunset. Bruce Roe
              Same as the claim for some wind turbines that they start with very low wind speeds - since there is little power in those low speed winds the power generated is zip.
              [SIGPIC][/SIGPIC]

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              • #22
                I plan on spending the $303 for a 20 year warranty regardless of which size I get, so lifespan isn't an issue. Probably a good idea - is it a 3rd party insurance type of warranty? The party themselves may well not be around.


                Originally posted by russ View Post
                Comments in bold within the text
                The warranty is through Solaredge. It's $303 for 20 years, I THINK $485 for 25. The 20 seems a good deal for something with a 12 year warranty. You just fill out a form after the install & mail them a check.

                The thing that keeps eating at me in this is that Solaredge advises to buy a cheaper inverter. If it was the other way around I'd write it off as marketing hype or something, but they have nothing to gain & $$ to lose by doing this.
                6k LG 300, 16S, 2E, 2W, Solaredge P400s and SE5000

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                • #23
                  Originally posted by bcroe View Post
                  I can't see your exact panel orientation, but here is how it would work here. Your 18 panels
                  are rated 4950W. If the 2 east facing panels were at 100% and 550W, I'd expect 10% of that
                  from the west facing 2 panels, 55W. Total is 5555W, with 97% inverter & DC wiring efficiency,
                  this amounts to 5388W output. In reality the E, S, and W facing will never be at peak anywhere
                  near the same time, so you probably will never be near clipping.
                  That is my feeling also. It seems like a safe bet even if the theory is crap.
                  6k LG 300, 16S, 2E, 2W, Solaredge P400s and SE5000

                  Comment


                  • #24
                    Originally posted by Bikerscum View Post
                    The warranty is through Solaredge. It's $303 for 20 years, I THINK $485 for 25. The 20 seems a good deal for something with a 12 year warranty. You just fill out a form after the install & mail them a check.
                    And if they are around in 15 years when the inverter fails they back it up - if they aren't? Some panel manufacturers offer a warranty backed by insurance that will pay even if they go belly up.
                    [SIGPIC][/SIGPIC]

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