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  • Which encapsulant is best

    Does anyone have any recommendation for encapsulating solar cells? What is the best regarding price, durability and easy to work with?

    Are there any significant differences between sylgard 184, qsil 216, syl-cell 1084, cell guard or eva-tedlar? Eva seems to be the hardest to work with?

    Any recommendation or experiences you could could share.

    Panels to be encapsulated: 60 6x6 cells, glass 173x95cm.

    Greatful for any help.

  • #2
    I can't give you a comparison, but Sylgard 184 is pretty easy to use. OK it's not exactly cheap, but you only use it once and it's worth the outlay.
    Takes about a week to cure fully.

    I made a 1m2 panel and my cells were not perfectly flat on the glass, one tub was just enough to do the job.

    Put a bead of silicone around the area you want to encapsulate, it might only be an inch or so around the border, but it will give you a little bit more to play with...
    Dem

    Comment


    • #3
      With larger cells, its hard to get the bubbles out between them and the glass. I took
      an old hand vibrator, attached it to a wood block, and bolted it to the panel frame.
      The voltage was gradually turned up with a variable transformer, till the level of
      vibration seemed OK. It worked, first time all the bubbles were gone.

      There is 1/4" square plastic rod epoxied around the edge to guide cells and
      contain the encapsulate, just visible. There are also 2" strips between columns
      of cells about every 6", as guides. Once its done, a backing can by laid on the
      plastic rod, used as spacers from the cells. Bruce Roe
      Attached Files

      Comment


      • #4
        Originally posted by bcroe View Post
        With larger cells, its hard to get the bubbles out between them and the glass. I took
        an old hand vibrator, attached it to a wood block, and bolted it to the panel frame.
        The voltage was gradually turned up with a variable transformer, till the level of
        vibration seemed OK. It worked, first time all the bubbles were gone.

        There is 1/4" square plastic rod epoxied around the edge to guide cells and
        contain the encapsulate, just visible. There are also 2" strips between columns
        of cells about every 6", as guides. Once its done, a backing can by laid on the
        plastic rod, used as spacers from the cells. Bruce Roe
        Bruce. Nice set up.

        Is that panel providing you the expected VA output and how old is it?

        Comment


        • #5
          Originally posted by SunEagle View Post
          Bruce. Nice set up.

          Is that panel providing you the expected VA output and how old is it?
          I made quite a few attempts back then, starting with what I saw on the internet.
          They all failed in a very short time. As a result I came up with this scheme. This
          last panel is a success, all good cells, and delivering the expected power. Guess
          it needs to be on display somewhere with the other stuff. Maybe power my
          stored vehicle battery maintainer, which can tolerate the intermittent PV power.
          About a year old, has several times as much encapsulant as allegedly needed.

          All those lessons taught me there was no way to come into the same ballpark
          of practicality of commercial panels, at under $1 a watt. There are over 150
          commercial panels here, 2/3 in daily service. Bruce Roe
          Attached Files

          Comment


          • #6
            Originally posted by bcroe View Post
            I made quite a few attempts back then, starting with what I saw on the internet.
            They all failed in a very short time. As a result I came up with this scheme. This
            last panel is a success, all good cells, and delivering the expected power. Guess
            it needs to be on display somewhere with the other stuff. Maybe power my
            stored vehicle battery maintainer, which can tolerate the intermittent PV power.
            About a year old, has several times as much encapsulant as allegedly needed.

            All those lessons taught me there was no way to come into the same ballpark
            of practicality of commercial panels, at under $1 a watt. There are over 150
            commercial panels here, 2/3 in daily service. Bruce Roe
            I agree that panel could be used for a vehicle battery tender. At least it will be put to use after all those hours and trials to build it.

            150 panels!!!. I never counted them from your pictures so I didn't realize how huge your system is.

            I remember you were looking to modify your Southern facing array so they could be tilted to reduce snow accumulations. Were you able to come up with a solution yet?

            Comment


            • #7
              Originally posted by bcroe View Post
              With larger cells, its hard to get the bubbles out between them and the glass. I took
              an old hand vibrator, attached it to a wood block, and bolted it to the panel frame.
              The voltage was gradually turned up with a variable transformer, till the level of
              vibration seemed OK. It worked, first time all the bubbles were gone.

              There is 1/4" square plastic rod epoxied around the edge to guide cells and
              contain the encapsulate, just visible. There are also 2" strips between columns
              of cells about every 6", as guides. Once its done, a backing can by laid on the
              plastic rod, used as spacers from the cells. Bruce Roe
              Thanks you for your insight. Looks very good. Maybe i have to order a "panel vibrator". I had planed to keep the panels enclined when poring the capsulant like this video shows: https://www.google.no/url?sa=t&sourc...vSLDB2HXGLyjPg

              Cell-syl or qsil seems to be the cheapest products for encapsulation.

              I am doing the diy panels as a project for fun/learning. Will probably buy solar panels later. For me here in Norway the "store bought" panels will cost around 2$ per watt. Online similar due to shipping cost and VAT. DIY panels around half that, but probably with much shorter time to failure.

              Comment


              • #8
                Originally posted by SunEagle View Post
                I agree that panel could be used for a vehicle battery tender. At
                least it will be put to use after all those hours and trials to build it.

                150 panels!!!. I never counted them from your pictures so I didn't realize how huge your system is.

                I remember you were looking to modify your Southern facing array so they could be tilted
                to reduce snow accumulations. Were you able to come up with a solution yet?
                Getting a bit off track here. There are 40 panels NOT deployed, you can't count them.
                Not a "classic" design: a NW IL design that generates KWH rain or shine.
                Although a lot of mods have been made, the original installer has inspected everything
                and found it to be completely compliant with all regs. The (grid connected) working panels
                are nicely keeping the house toasty, with the aid of a heat pump. If this winter keeps
                letting me run the heat pump, there might be a big KWH surplus.

                Keeping the snow off hasn't made concrete progress. It should work to an absolute minimum
                of manual intervention. Getting them vertical for snow season ought to help a lot, but
                changing them manually twice a year is a BIG project. Maybe a mechanism to set them just
                over vertical each snow fall could work well (and void the warrantee), but that means a
                complete support redesign with built in activators; a long term project. With all snow
                falling off the front (instead of pushed off sides & top), they might need to be higher off
                the ground to clear accumulation. An alternative is near vertical all winter with ELECTRIC
                defrosting as needed, also a very big project that likely voids the warrantee. Tests on my
                DIY panel indicate it is doable. Maybe should set up a spare 250W and test the idea now!

                There is another thought to put all the east facing panels at the west side of the clearing
                to minimize shading; west facing located far east. All this could be done at one time,
                some year. Bruce Roe

                Comment


                • #9
                  Originally posted by bcroe View Post
                  Getting a bit off track here. There are 40 panels NOT deployed, you can't count them.
                  Not a "classic" design: a NW IL design that generates KWH rain or shine.
                  Although a lot of mods have been made, the original installer has inspected everything
                  and found it to be completely compliant with all regs. The (grid connected) working panels
                  are nicely keeping the house toasty, with the aid of a heat pump. If this winter keeps
                  letting me run the heat pump, there might be a big KWH surplus.

                  Keeping the snow off hasn't made concrete progress. It should work to an absolute minimum
                  of manual intervention. Getting them vertical for snow season ought to help a lot, but
                  changing them manually twice a year is a BIG project. Maybe a mechanism to set them just
                  over vertical each snow fall could work well (and void the warrantee), but that means a
                  complete support redesign with built in activators; a long term project. With all snow
                  falling off the front (instead of pushed off sides & top), they might need to be higher off
                  the ground to clear accumulation. An alternative is near vertical all winter with ELECTRIC
                  defrosting as needed, also a very big project that likely voids the warrantee. Tests on my
                  DIY panel indicate it is doable. Maybe should set up a spare 250W and test the idea now!

                  There is another thought to put all the east facing panels at the west side of the clearing
                  to minimize shading; west facing located far east. All this could be done at one time,
                  some year. Bruce Roe
                  Back on topic.

                  Based on your "hands on" experience it is nice to let others know that there are proven ways to properly encapsulate the cells in a DIY panel which will produce a final working product. Although also providing some background that it will take more than a few trials to get a working product may help others think about what they are getting into.

                  As for the off topic, I like your idea of switching the E & W arrays to minimize shading issue.

                  Comment


                  • #10
                    Originally posted by paara View Post
                    Thanks you for your insight. Looks very good. Maybe i have to order a "panel vibrator". I had planed to keep the panels enclined when poring the capsulant like this video shows:

                    Cell-syl or qsil seems to be the cheapest products for encapsulation.

                    I am doing the diy panels as a project for fun/learning. Will probably buy solar panels later. For me here in Norway the "store bought" panels will cost around 2$ per watt. Online similar due to shipping cost and VAT. DIY panels around half that, but probably with much shorter time to failure.
                    I did some tilting of my panel, but not a lot or the encapsulant would run over my 1/4" high
                    plastic rails. I think the vibrator might be less labor intensive; maybe a combination is best.
                    Or build that vacuum chamber to urge the air out. I load tested cells before hand; I think
                    more practical & through than trying to test them after soldering & before encapsulation. A
                    voltmeter won't detect a low current (cracked) cell.

                    There are bus jumpers at the ends of every column; I found these laborsome to make to
                    close dimensions. The 1/4" wide tabbing was quickly bent over this jig to a height of 1/4"
                    (above the encapsulant), cut to the ink lines for the panel output. For jumping between
                    columns of cells, the bus length was made the total jig length. These were epoxied to the
                    glass in advance, just outside the cell area.

                    For most panels I bought aluminum and tempered glass from industrial sources; much cheaper
                    than retail. Then there's hardware, cells, encapsulant, other stuff. While my 1/4" square spacers
                    did keep things in place, they reduced the useful area of the panel. Here it just doesn't add up
                    financially. Bruce Roe
                    Attached Files

                    Comment


                    • #11
                      Prices for encapsulant on ebay including shipping:
                      -Sylgard 184: 359$ for 6,6 pound
                      - Qsil 216: 220$ for 6,6 pound
                      - Syl cell 1084: 188$ for 7,7 pound
                      - Cell gard: 288$ for 6,6 pond

                      Has anyone used Syl-cell? It is the cheapest, and if the aforementioned products are somewhat similar I am thinking of going for this.


                      Did some calculation to check approximately overall price which include shipping and VAT: 1$ per watt. (2kw cells, bypassdiods, tabbing/bussbar. I bought 2kw worth of solar cells so I could make another 1kw panels if the result is okay for a lot less. Glass and frame I have for free.) Labour will be for free since this is a hobby project, but would probably amount to 2-3x material cost if included. Thus my conclusion is as many times mention in this DIY forum section. DIY will not save money (in the long run), but that was never the point.

                      Comment


                      • #12
                        Why not do what the solar panes manufacturers do?

                        Make sure the cells are cleaned with 99% iso alcohol in an ultrasonic cleaner... Solder them, place them face down on glass, place a sheet of EVA (EVA is cheap) over the backs of the cells.

                        Since you are a home brewer, tape the edges of the EVA to the glass, except for one spot. Tape the end of a vacuum to the small open spot, turn the vacuum on. It will suck out all the air and achieve a uniform coverage. Using a heat gun, heat the EVA until it adheres to the glass, going on down.

                        After that all that is needed is to attach the borders, and run the wires into a hook up box.

                        I wouldn't trust any adhesives. I have two Carizo solar cells that are older, that have yellowed significantly from the glue they used back in the day. EVA is the way to go. And it's cheap. You'll find the most expensive part is the tempered glass. You cannot use standard glass, it will shatter and ruin your panel. You have your pick of borders, as long as it supports the glass and keeps it safe.

                        Here you go:

                        https://www.youtube.com/watch?v=FAFMv-X9IkE

                        Comment


                        • #13
                          Originally posted by thehandyman View Post
                          Why not do what the solar panes manufacturers do?
                          Make sure the cells are cleaned with 99% iso alcohol in an ultrasonic cleaner... Solder them, place
                          them face down on glass, place a sheet of EVA (EVA is cheap) over the backs of the cells.

                          Since you are a home brewer, tape the edges of the EVA to the glass, except for one spot. Tape the end of a vacuum to the small open spot, turn the vacuum on. It will suck out all the air and achieve a uniform coverage. Using a heat gun, heat the EVA until it adheres to the glass, going on down.
                          After that all that is needed is to attach the borders, and run the wires into a hook up box.

                          I wouldn't trust any adhesives. I have two Carizo solar cells that are older, that have yellowed significantly from the glue they used back in the day. EVA is the way to go. And it's cheap. You'll find the most expensive part is the tempered glass. You cannot use standard glass, it will shatter and ruin your panel. You have your pick of borders, as long as it supports the glass and keeps it safe.
                          Here you go: https://www.youtube.com/watch?v=FAFMv-X9IkE
                          I couldn't pick up cells that were already soldered together, they would break.

                          So the cells would just be lying directly on the glass; what is to keep a large column from
                          just sliding to the bottom when the panel is vertical? The EVA holds everything, but with
                          the (not connected) cells in between, how does it connect to the glass? Seems like there
                          would be very little contact. What sort of vacuum would be used, and what kind of heat
                          to seal the EVA? I envision the edges of the EVA being sucked under cells. Bruce Roe

                          Comment


                          • #14
                            Originally posted by bcroe View Post
                            I couldn't pick up cells that were already soldered together, they would break.

                            So the cells would just be lying directly on the glass; what is to keep a large column from
                            just sliding to the bottom when the panel is vertical? The EVA holds everything, but with
                            the (not connected) cells in between, how does it connect to the glass? Seems like there
                            would be very little contact. What sort of vacuum would be used, and what kind of heat
                            to seal the EVA? I envision the edges of the EVA being sucked under cells. Bruce Roe
                            Have you ever examined the back of a commercial solar panel?

                            The EVA adheres to the cells AND the glass. When the heat gun is applied to the back, it transforms from solid-flexible to near liquid. It will not go between the cells and the glass unless there is a thick solder joint preventing the cells from laying flat against the glass.

                            Properly done, as in the video I showed you, the EVA in its super heated state will melt (And is pulled in by vacuum, start heating furthest from the vacuum connection as possible. Work towards where the vacuum is connected so you do not accidentally clock the vacuum action. It will melt to the glass, too, isolating each individual solar cell, providing that you spaced them out enough, usually 1/8" is fine.

                            For example, I have a commercial Sharp panel @ 250 watts that has a bag cell, with a perforation penetrating the EVA. the cell is discolored, but it is separate from all the rest.

                            Just make sure you have the cells spaced far enough apart from each other. If your current cell column is too close, you can try it, but in the future, make sure they lay perfectly flat, and space them out using ceramic tile spacers from Lowes.

                            Comment


                            • #15
                              EVA is a hot melt glue, used between the Glass and the cell wafers. When heated it goes clear and flows.

                              TEDLAR is used as the white back sheet, it's adhered to the back side of the wafers somehow (maybe another sheet of EVA, I am not sure how the stack is made anymore)

                              The front side glass is a UV blocker, and the white tedlar is UV resistant and water vapor proof. The EVA will slow water vapor, but it is not absolute.

                              Fieldlines board has a great post/tutorial on how to do it right:
                              Oztules' series (at Fieldlines):
                              http://fieldlines.com/board/index.ph...,144982.0.html
                              http://fieldlines.com/board/index.ph...,144995.0.html
                              http://fieldlines.com/board/index.ph...,145004.0.html

                              Learn from them.
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                              || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                              || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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