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bewildered by panel choices for DIY system

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  • #16
    Originally posted by RShackleford View Post
    Worth the extra cost and imperfect appearance ?

    So what do folks think of these brands, and are there others that might be more attractive to me ?
    IMO panel choice is the least important consideration; Even racking is more important. If you want black panels for aesthetics get black panels. If you're space constrained get higher wattage panels; If you're on a budget get the cheapest ones (So long as they're UL) even 'B' grade is fine IMO. I've bought B grade.... it's usually just a cell misalignment that doesn't effect performance and can only be see if you're on the roof inches away from the panel.

    If cost is a concern Renvu is selling Talesun panels for $0.36/w.

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    • #17
      Originally posted by nwdiver View Post
      Even racking is more important.
      What can be got wrong there ? Are you talking about azimuth & elevation, or more subtle issues ?


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      • #18
        Originally posted by RShackleford View Post
        That's a very good question, to which I don't know the answer. All I know is that it's an input to PVWatts, and it's the number an installer used in PVWatts to estimate the number of kwh I should generate per year (a number which they are guaranteeing). The installer came up with the number by getting up on my roof with some sort of electronic device.


        I am planning ground-mount. One reason being that the location would be a bit sunnier, though not dramatically so, than the roof.

        Soooooooooo! You have 5 acres and it only gets a total of 70% Sun half the day/night that's an 80% loss? Invest in a really good chain-saw. Problem solved.

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        • #19
          Yeah, I saw those. Doing ground-mount, I'm not so space-constrained. Nor do I have a rigid idea of how many watts I need.

          I've made a spreadsheet to compare a variety of specific panels, configuration (number of panels and landscape/portrait), etc. I assume a $50 optimizer on every panel (Tigo TS4-R-O) and $3500 in add'l costs that are fixed regardless of these other choices (inverter, racking, structure, basically from the OP of this thread). Doing that, a 15 panel system with the Canadian 320watt panels is not much more per watt ($1.54) than the Talesun would be ($1.46), and gives me a good bit more wattage (4800 versus 4050). IOW, those bargain panels don't help me that much because of all the other costs.
          Screen Shot 2019-11-07 at 4.04.22 PM.png
          The "panels $" column is a little hinky, because the various panels come from different vendors, all of whom compute shipping separately (flat fee, or some value the shopping cart just computes based on weight or something).

          Comment


          • #20
            Originally posted by Paul Land View Post
            Soooooooooo! You have 5 acres and it only gets a total of 70% Sun half the day/night that's an 80% loss? Invest in a really good chain-saw. Problem solved.
            Not sure where "half the day/night" comes from, but yeah, only 70% if I believe the 30% shading.

            I have a good chainsaw. But I have a LOT of trees.


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            • #21
              Originally posted by RShackleford View Post
              Not sure where "half the day/night" comes from, but yeah, only 70% if I believe the 30% shading.

              I have a good chainsaw. But I have a LOT of trees.

              1/2 (50%) of the day is Night and it's dark

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              • #22
                Originally posted by Paul Land View Post

                1/2 (50%) of the day is Night and it's dark
                Don't think a chainsaw will help too much with that. And really, the vast majority of your production comes from about a 6hr period centered around local noon.

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                • #23
                  Originally posted by RShackleford View Post
                  What can be got wrong there ? Are you talking about azimuth & elevation, or more subtle issues ?

                  Well.... your panels can blow away; We used new racking from unirac that had poor lateral support for the end panels and one of the panels broke loss in a storm. We're lucky the entire top row didn't 'unzipper'.

                  Originally posted by RShackleford View Post

                  Yeah, I saw those. Doing ground-mount, I'm not so space-constrained. Nor do I have a rigid idea of how many watts I need.

                  I've made a spreadsheet to compare a variety of specific panels, configuration (number of panels and landscape/portrait), etc. I assume a $50 optimizer on every panel (Tigo TS4-R-O)
                  If you're doing a ground mount and you're trying to keep your costs low I wouldn't use optimizers. Rapid Shutdown is only required for roof mount. There's no ROI especially if you can buy panels for $0.36/w and you're not space constrained. I guarantee that every $1 spent on optimizers will be >5x more productive if you just buy more panels.
                  Last edited by nwdiver; 11-07-2019, 05:44 PM.

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                  • #24
                    Originally posted by RShackleford View Post
                    I've made a spreadsheet to compare a variety of specific panels, configuration (number of panels and landscape/portrait), etc.
                    I just found out that the new REC alpha will be available in 355W panels in a couple of weeks for $0.75/W ($266 for 355 watts) which is quite nice for a panel of that quality
                    -0.26 temp coef
                    Cut Cell panel (6 strings of 20 cells)
                    92% production warranty at 25 years
                    20 years product warranty
                    https://www.recgroup.com/sites/defau...v_b_en_web.pdf

                    No dates and price yet on the 380Watt version

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                    • #25
                      Originally posted by scrambler View Post

                      I just found out that the new REC alpha will be available in 355W panels in a couple of weeks for $0.75/W ($266 for 355 watts) which is quite nice for a panel of that quality
                      -0.26 temp coef
                      Cut Cell panel (6 strings of 20 cells)
                      92% production warranty at 25 years
                      20 years product warranty
                      https://www.recgroup.com/sites/defau...v_b_en_web.pdf
                      Wow. What vendor ?

                      Comment


                      • #26
                        Originally posted by scrambler View Post
                        I just found out that the new REC alpha will be available in 355W panels in a couple of weeks........
                        That's gonna be an armload up on a roof !
                        Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                        || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                        || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                        solar: http://tinyurl.com/LMR-Solar
                        gen: http://tinyurl.com/LMR-Lister

                        Comment


                        • #27
                          Originally posted by Mike90250 View Post

                          That's gonna be an armload up on a roof !

                          I think the OP is doing a ground mount. And those are half-cells so it's not much bigger than a standard 60 cell and much smaller than a 72 cell.

                          Comment


                          • #28
                            Originally posted by RShackleford View Post
                            Wow. What vendor ?
                            Solar Electric Supply
                            https://www.solarelectricsupply.com/...ce-solar-panel

                            Comment


                            • #29
                              Originally posted by Mike90250 View Post

                              That's gonna be an armload up on a roof !
                              They are almost the same size as LG 325 or Qcell 325 (67.75 x 40)

                              Comment


                              • #30
                                Originally posted by nwdiver View Post
                                ....................... And those are half-cells so it's not much bigger than a standard 60 cell and much smaller than a 72 cell.
                                If the half cells are twice as efficient, that might be true, but I know of no breakthrough allowing 355w panels to be smaller than 250W panels.

                                355w is still going to take up some real-estate, be heavy and act like a sail.


                                43 lbs, 68" x 40" , 20.3% eff

                                Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                                || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                                || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                                solar: http://tinyurl.com/LMR-Solar
                                gen: http://tinyurl.com/LMR-Lister

                                Comment

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