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  • Originally posted by SunEagle View Post
    I just saw a flyer yesterday about a new type of panel tracker made by
    HAS. I don't know the cost but it looked pretty impressive.
    It looks like an industrial design, made in this area. Doesn't appear to do 2 axis. I hope they find
    some customers; trackers are less valuable with clouds and cheap panels. Maybe its for industrial
    applications, are some of those single tilt axis? Bruce Roe

    Comment


    • Originally posted by bcroe View Post
      It looks like an industrial design, made in this area. Doesn't appear to do 2 axis. I hope they find
      some customers; trackers are less valuable with clouds and cheap panels. Maybe its for industrial
      applications, are some of those single tilt axis? Bruce Roe
      It looks like a single axis movement. What impressed me was they were using a Parker cylinder hydraulic system which are pretty well designed to last.

      Comment


      • Originally posted by bcroe View Post
        It looks like an industrial design, made in this area. Doesn't appear to do 2 axis. I hope they find
        some customers; trackers are less valuable with clouds and cheap panels. Maybe its for industrial
        applications, are some of those single tilt axis? Bruce Roe
        A good number of industrial applications use multipanel long row horizontal axis tracking.
        Particularly good performance close to the equator.

        I saw a clip last year about a system where a robotic actuator worked its way down the row tilting panels and leaving them fixed in place as it went.
        Next scheduled axis change it worked its way back up the row.

        One actuator for many panels.
        SunnyBoy 3000 US, 18 BP Solar 175B panels.

        Comment


        • Originally posted by inetdog View Post
          A good number of industrial applications use multipanel long row horizontal axis tracking.
          Particularly good performance close to the equator.

          I saw a clip last year about a system where a robotic actuator worked its way down the row tilting panels
          and leaving them fixed in place as it went. Next scheduled axis change it worked its way back up the row.

          One actuator for many panels.
          This I've got to see. I have bolts to move & tighten on my 2013 version. The activators might be
          here Friday, seem quite heavy. The robot moving them will be human. Don't know if I have a power
          supply big enough for a pair of 24VDC motors, or will need to make something. Bruce Roe

          Comment


          • Originally posted by bcroe View Post
            This I've got to see.
            I am not sure if this was the one that I saw, but here is a 2012 article about the system. http://www.technologyreview.com/view...-solar-panels/
            Unfortunately for them the idea did not catch on and the company stopped operations just this month.
            SunnyBoy 3000 US, 18 BP Solar 175B panels.

            Comment


            • Originally posted by bcroe View Post
              Here is the energy reserve to date for next winter, with the 2 previous years. Generation isn't any
              better than a year ago; probably a little worse (more clouds). Its got a jump on last year, because
              this year I was heating with a new heat pump in the spring. Bruce Roe
              The electric bill came; here is the latest energy reserve buildup for winter. Despite even more clouds
              than last year, I'm well above 2014. The heat pump gets most of the credit; usage here is quite small
              (due to earlier conservation efforts) except when the heat goes on. Most of what the PV generates
              is going to reserve, but that will change soon. If the winter is actually the predicted warmer, there
              might be a big surplus. Bruce Roe
              Attached Files

              Comment


              • Pv snow gap & linear activator

                Originally posted by bcroe View Post
                Its getting late, but I may yet manage to get my south facing panels vertical for this snow season. The
                24 braces to hold them are done; the issue is how to raise & lower each platform having two braces.

                I ordered a couple linear actuators with a 52 inch stroke (about enough) and a 5000 lb capacity (overkill).
                They run on 24 VDC, should be able to fine control them with adjustable voltage.

                But they haven't arrived yet, so the mechanical design is still in doubt. Worst case the whole thing will
                fall on me. IREA tour this Sat. Bruce Roe
                Today was the setup for another snow experiment. I have panels 2 high, meaning snow must
                slide a long way to be cleared off 2 panels, and the pile of snow gets pretty big while clearing and
                at the bottom. On one support of 6 panels I moved the upper panels 4" higher and the lower panels
                2" lower for a 6" gap between them. Snow will only need to slide half as far, in half the quantity
                before falling through the gap.

                On the next support of 6 panels, I just moved the upper for a gap of 4". This winter will be the
                test: does the gap work and how big should it be? Did it in the afternoon, had just enough sun
                time left to make sure all were still working properly.

                I did get the linear activators unpacked and they run; take about 10 minutes at 18V to run 52
                inches. I suppose that means 180 volt minutes for 52 inches: 7.5 minutes at 24V or 15 min at
                12V. The draw is only around 2A once they get started, not the 12A on the plate. Getting them
                driving a panel platform remains in the future. Bruce Roe

                Comment


                • Originally posted by bcroe View Post
                  The draw is only around 2A once they get started, not the 12A on the plate. Getting them
                  driving a panel platform remains in the future. Bruce Roe
                  Most likely the 12A is when working against the maximum rated force.
                  SunnyBoy 3000 US, 18 BP Solar 175B panels.

                  Comment


                  • Originally posted by bcroe View Post
                    The electric bill came; here is the latest energy reserve buildup for winter.
                    Despite even more clouds
                    than last year, I'm well above 2014. The heat pump gets most of the credit; usage here is quite small
                    (due to earlier conservation efforts) except when the heat goes on. Most of what the PV generates
                    is going to reserve, but that will change soon. If the winter is actually the predicted warmer, there
                    might be a big surplus. Bruce Roe
                    An update; energy reserve for winter heat is peaking about now, 2000 KWH or 16% higher than last
                    year. The unseasonably warm weather has kept generation in the black for some extra days.

                    Energy generated since annual reset 1 April is almost exactly the same as last year, 19,600 KWH.
                    That despite more clouds, probably aided by removal of some shade. However the weather and the
                    new heat pump have reduced consumption in the interval. Its interesting how much things can
                    vary from year to year. If we have the predicted mild winter, I will be doing some electric heat
                    in another building. Bruce Roe
                    Attached Files

                    Comment


                    • Panel wiring order

                      I was wondering about considerations for the order of wiring a string of PV panels?
                      I understand perhaps stringing a row, dropping to a second row, and stringing back
                      to the beginning. Or stringing every other panel in a single row, then stringing back
                      on the other panels to the beginning.

                      I have strings of 12 panels here, on 2 ground mount platforms of 2 high and 3 across.
                      The installer connected one platform in a rectangle, 3 across the top and then down
                      to 3 back across the bottom. The other platform is a zig zag; bottom to top, across
                      and then back to bottom, across and then back to top. Perhaps this was to get both
                      feed points as far east as possible. Some strings are fed from the east, but a string
                      with the feed between platforms is wired the same.

                      i was thinking about voltage induced in the big loops by a near lightening strike. If
                      my 2 platforms were wired exactly the same, the voltage induced in the wiring of
                      the two platforms would add up and be seen at the inverter. If the panel wires
                      were crossed on the second platform, clockwise current in one would be
                      counter clockwise current in the other. Voltages induced in the two platform
                      loops would be reversed and tend to cancel.

                      This came up when I put a "snow drop" gap between upper and lower rows of
                      panels. The rectangular pattern had 2 wires crossing the snow gap, which I
                      can protect from ice & snow by tying them under the vertical supports. The zig
                      zag pattern had 4 wires, 2 with no nearby supports. My thought is to eliminate
                      the zig zag and the 2 extra wires crossing the gap. Bruce Roe

                      Comment


                      • Originally posted by bcroe View Post
                        I was wondering about considerations for the order of wiring a string of PV panels?
                        I understand perhaps stringing a row, dropping to a second row, and stringing back
                        to the beginning. Or stringing every other panel in a single row, then stringing back
                        on the other panels to the beginning.

                        I have strings of 12 panels here, on 2 ground mount platforms of 2 high and 3 across.
                        The installer connected one platform in a rectangle, 3 across the top and then down
                        to 3 back across the bottom. The other platform is a zig zag; bottom to top, across
                        and then back to bottom, across and then back to top. Perhaps this was to get both
                        feed points as far east as possible. Some strings are fed from the east, but a string
                        with the feed between platforms is wired the same.

                        i was thinking about voltage induced in the big loops by a near lightening strike. If
                        my 2 platforms were wired exactly the same, the voltage induced in the wiring of
                        the two platforms would add up and be seen at the inverter. If the panel wires
                        were crossed on the second platform, clockwise current in one would be
                        counter clockwise current in the other. Voltages induced in the two platform
                        loops would be reversed and tend to cancel.

                        This came up when I put a "snow drop" gap between upper and lower rows of
                        panels. The rectangular pattern had 2 wires crossing the snow gap, which I
                        can protect from ice & snow by tying them under the vertical supports. The zig
                        zag pattern had 4 wires, 2 with no nearby supports. My thought is to eliminate
                        the zig zag and the 2 extra wires crossing the gap. Bruce Roe

                        I have two arrays of 36 panels each. Each array has 3 strings of 12 panels each. Each array is configured into 4 rows of 9 panels wide.

                        I am now on the third wiring method. Initially the wiring method was top to bottom.....the thinking being that snow would slide to bottom rows thus exposing the the top rows to produce at full power. Since I pull the snow it was not really needed since all rows are exposed by my effort.

                        Next wiring effort was to wire the strings so that all the string lengths were equal to the combiner boxes. Thus the voltage loss on each string length would be equal. Not sure if it made any difference but it sounded electrically elegant.

                        Then I got the bright idea that if I wired the strings left to right in blocks I would follow the shading across the arrays as the sun rose. Thus maximizing production in the mornings. So I have stuck with this method.

                        Now Bruce you come along with your lightning strike voltage loop theory.......hmmmmmm.

                        Comment


                        • Originally posted by DanS26 View Post
                          I have two arrays of 36 panels each. Each array has 3 strings of 12 panels each.
                          I am now on the third wiring method.

                          I got the bright idea that if I wired the strings left to right in blocks I would follow the shading across the arrays as the sun rose. Thus maximizing production in the mornings. So I have stuck with this method.
                          I just want to hear any wisdom on the subject. I have a 65' radio tower 200' away (300' from
                          the house), but it hasn't been hit by lightning yet. I have the same, 6 strings of 12 panels facing
                          south. And wired in blocks so shade will only affect an end. However there are more strings
                          facing east and west. Bruce Roe

                          Comment


                          • Originally posted by bcroe View Post
                            I just want to hear any wisdom on the subject. I have a 65' radio tower 200' away (300' from
                            the house), but it hasn't been hit by lightning yet. I have the same, 6 strings of 12 panels facing
                            south. And wired in blocks so shade will only affect an end. However there are more strings
                            facing east and west. Bruce Roe
                            For the overall leads exiting the array at the same point, the wiring method in between should not have a large effect on the induced voltage in the loop of wire that connects the panels within the array.
                            Just out of superstition I would look at the arrangement that
                            1. Had the lowest possible total length of wire, but
                            2. Had the + and - leads running next to each other whenever possible if there are any long runs.
                            SunnyBoy 3000 US, 18 BP Solar 175B panels.

                            Comment


                            • Originally posted by bcroe View Post
                              I just want to hear any wisdom on the subject. I have a 65' radio tower 200' away (300' from
                              the house), but it hasn't been hit by lightning yet. I have the same, 6 strings of 12 panels facing
                              south. And wired in blocks so shade will only affect an end. However there are more strings
                              facing east and west. Bruce Roe
                              Only a matter of time until that tower is struck. You are wise to be concerned about voltage gradients affecting your solar system.

                              I too am concerned about lightning since my location has been struck multiple times and lost much electronics and appliances. That was over ten years ago when my electrical system was your basic 1950's farm electrical system......two wire system with multiple neutral ground bonding all over the place and multiple unconnected ground rods. It all came to a head when my wife would be shocked by touching the washing machine and standing on the concrete basement floor in bare feet. The shock was in time with the electric fence charger.

                              Then I got serious. Completely rewired the farm to 2011 NEC specs. Modern three or four wire system as required and unbonded the neutrals except in the main disconnect. Had some close strikes since then but no damage.

                              My arrays are ~250 ft from the house and each has a ground ring around the array. Each ring has four rods and bonded to each other. Probably overkill since each array has ten 3" galvanized steel posts encased in concrete 4 feet deep.

                              An EGC connects the combiner boxes at the arrays to the inverters at the house. Of course that is for personal protection and probably would do little to protect from lightning. I believe the theory is that the resistance in the length of the EGC would make a strike go to ground fast at the array or the house before jumping above ground and damaging equipment.

                              Lastly I rely on multiple SPD's all over the place, even one on the pole transformer, under the meter, in all sub panels and combiners, both inverters and all detached structures. 18 at last count and does not include the SPD's at point of use.

                              Comment


                              • Originally posted by DanS26 View Post
                                I have two arrays of 36 panels each. Each array has 3 strings of 12 panels each. Each array is configured into 4 rows of 9 panels wide.

                                I am now on the third wiring method. Initially the wiring method was top to bottom.....the thinking being that snow would slide to bottom rows thus exposing the the top rows to produce at full power. Since I pull the snow it was not really needed since all rows are exposed by my effort.

                                Next wiring effort was to wire the strings so that all the string lengths were equal to the combiner boxes. Thus the voltage loss on each string length would be equal. Not sure if it made any difference but it sounded electrically elegant.

                                Then I got the bright idea that if I wired the strings left to right in blocks I would follow the shading across the arrays as the sun rose. Thus maximizing production in the mornings. So I have stuck with this method.

                                Now Bruce you come along with your lightning strike voltage loop theory.......hmmmmmm.
                                Dan that 72 panel array sounds huge. Have you posted any pictures of it?

                                Comment

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