Phase two of the DIY solar panel project is a fresh start with a larger and much higher output panel design. With lessons taken from the first project and further research under the belt there is no question this and future panels built will be far superior to the first (hopefully rivaling commercially available units). So it’s time to get this show on the road.
After exploring different dimensions and layouts using inexpensive CAD software installed on one of our computers, a combination of online and local comparison shopping took place. Buying aluminum bar locally is more expensive than ordering online. That may be subject to change as I continue researching local suppliers. Clear acrylic (AKA plexiglass) 30” X 60” X .080” thick are available locally for about $22 each. Going with different dimensions would mean buying 48” X 96” sheets at about $90 and personally cutting the pieces to size. Time required, the risk of ruining at least half a $90 acrylic sheet versus getting two 30” X 60” pieces for under $50 made going with already cut pieces economical and logical. So acrylic it is for both the front and back panels. Aluminum sheet can be used for the back panel but higher cost and added work electrically insulating the aluminum makes the acrylic a more practical choice.
Brief side notes here: First, mostly as a matter of economics .080” thick acrylic was chosen. Also available are 30” X 60” X .118” thick pieces at about $33 each. Tempting though it is, this first larger panel will incorporate .080” thick acrylic. Second, clear polycarbonate may be worth considering but was ruled out for this project due to cost.
Before actual panel construction begins a couple simple jigs and a suitable work surface is planned. Details including video are in the works.
The first order of construction will be cutting 1” X .25” aluminum bar to yield 2 pieces 30” in length and 2 pieces 58” in length. Those pieces will become the perimeter of the solar panel. It will look pretty much like this:
Perimeter Frame
The aluminum will be secured to one acrylic panel which will become the back panel. The soldered together solar cells will be secured to the back panel using silicone cement.
One thing learned quickly when working with solar cells is they are quite fragile so careful handling is important. Likewise once mounted into the panel framework it is desirable not to allow front and rear panels to flex toward each other causing potential damage to the solar cells. To assure that does not present a problem 3 aluminum spacers .25” X .25” X 48” will be incorporated between the acrylic panels:
Frame With Spacers
Six inch square solar cells will be used and configured into four rows with nine cells per row.
Cells Layout
Once all soldering of cells is completed the back sides of the cells will be facing upward and will then have a coating of silicone cement painted over them to provide encapsulation. When the silicone is cured, dabs of silicone cement will be placed on each cell, the frame with back panel and spacers will be lowered into place over the cells and the silicone will be allowed to cure and bond the cells to the rear panel. When cured, the frame with cells in place will be flipped over and the cells front sides will then be encapsulated with clear optical grade silicone cement before sealing the front panel in place.
Complete Assembly
That’s the down and dirty version. There is considerably more than detailed above but you will just have to keep coming back for all the sordid details as they unfold.
Hey, I was thinking of building a similar (144w, from 6″ cells) panel. Can you shed any light on the encapsulation of the cells and creating a weatherproof environment for the cells?
Hi Islandsolar, apologies for slow response time. DIY builders sometimes use two part crystal clear optical grade silicone painted onto the cells. One such product is from GE and another is from Dupont. The Dupont product is less expensive but my research indicates it works equally well. Because of cost one method uses it to coat the front side of the cells and standard silicone coats the back.
Research regarding adhesives, sealants and encapsulation materials turned up information regarding silicones is making me rethink the use of silicone on cell backs either as a protective barrier or the means of holding them to the rear panel. Next post in the “Phase Two” series is being edited and deals with findings important to the issue.
Ethylene-Vinyl Acetate (EVA) sheet is another product used for the purpose. Claims are made that it has the potential to provide 700 plus years protection. Guess I won’t be hanging around long enough to learn if that’s true.
I’m also looking into possible use of an aerosol that could make encapsulation a snap if it is suitable.
I don’t know for sure but suspect if the cells are housed in a space with most of the air evacuated there may be little if any reason to encapsulate the panel cells.