Buying enough solar panels to give you sufficient electrical power for much of anything can be expensive. Each solar panel really doesn’t produce all that much power, so it takes a lot of them to get enough to run your home. I got a quote for $60,000 once, which I thought was totally ridiculous. The good news is, you can make those solar panels yourself.
How many volts solar cells produce?
Solar cells each produce 0.5 volts, regardless of their size. The larger ones produce more wattage, but it’s still at 0.5 volts DC. Most solar panels are designed to have a nominal 18 volt output, so that they will still produce over 12 volts to charge batteries, when not running at full efficiency. So, 36 solar cells, wired in series, will produce that 18 volts. While any size can be used, 3”x 6” solar cells are the most common for homemade solar panels.
Each solar cell has a positive and negative side. So, the wires connecting them together, called “tabbing wires” need to go from the positive side of one cell to the negatives side of the next. The cells are strung together in this way, with the cells as close together as possible and nine cells in a string. Then four strings are connected together, side by side, using wire called “buss wire.” The results in a rectangle of cells, about 24” x 27”.
Solar cells are extremely fragile
Before you try that, let me tell you about one other detail. That is, the solar cells, which are extremely fragile. Need to be mounted to some sort of backboard, either thin plywood or plastic. Silicone caulk works well for this. Simply put a line of dots on the backboard, then gently press the strung together solar cells into it, putting pressure only on the point just above the silicone. This should be done after the strings are made, but before the strings are connected together with the buss wire.
When laying this out, keep in mind that you’re really making one long string out of the four strings, just like lining up a lot of batteries for a flashlight. So, to make it easy to connect the positive end of one string to the negative end of the adjacent string, reverse the direction of each string, when compared to the previous one.
Okay, so now you’ve got four stings of cells mounted to a backboard and connected together, making one long string out of them. Attach connecting wires to the ends of the string and the electrical part of the solar panel is done. Now all you need is to encapsulate it.
How to build a front
This isn’t all that hard to do either. You’ve already got a back. Now all you need is a front, the glazing, and a frame. For glazing you can use normal window glass, tempered glass, Plexiglas or Lexan (given in order of ascending strength). Cut the pieces to the same size as the backboard.
It’s going to be necessary to keep the glazing from touching the solar cells, so that they don’t break. Some sort of spacer is needed. One thing that works is the double-sided foam tape that is often used for hanging pictures. Two layers are required, so as to hold the glazing up high enough. But that foam tape also has the advantage of holding the whole thing together.
Building the frame
All that’s needed then is a frame, which can be made out of aluminum C channel, cut to give mitered corners. Glue it in place with even more silicone caulk, sealing the edges all the way around. Just don’t forget to leave a hole for your wires to come out. Let the caulk dry and the panel will be ready for use.
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