MNN - Mother Nature Network

Mike Davis is an astronomer. To practice his hobby away from the light pollution of cities, he bought some land in a remote part of Arizona. But there was a problem: No electricity. But he's a resourceful fellow. He built some solar panels using inexpensive blemished and damaged solar cells from eBay!

 

Read on for more photos and some technical details to give you an idea of how he did it. (The following is quoted from his website, with edits as noted.)

 

I bought a couple of bricks of 3 X 6 mono-crystalline solar cells. It takes a total of 36 of these type solar cells wired in series to make a panel. Each cell produces about 1/2 volt. 36 in series would give about 18 volts which would be good for charging 12 volt batteries. (Yes, you really need that high a voltage to effectively charge 12 volt batteries.) This type of solar cell is as thin as paper and as brittle and fragile as glass.

 

A solar panel is really just a shallow box. So I started out by building myself a shallow box. I made the box shallow so the sides wouldn't shade the solar cells when the sun comes at an angle from the sides.

 

Next I cut two pieces of masonite pegboard to fit inside the wells. These pieces of pegboard will be the substrates that each subpanel will be built on. [...] To protect the solar cells from the weather, the panel will have a Plexiglas front.

 

I laid out the cells on that grid pattern upside-down so I could solder them together. All 18 cells on each half panel need to be soldered together in series, then both half panels need to be connected in series to get the desired voltage. [...]

 

I used a low-wattage soldering iron and fine rosen-core solder. I also used a rosen pen on the solder points on the back of the cells before soldering. Use a real light touch with the soldering iron. The cells are thin and delicate. If you push too hard, you will break the cells.

 

Here's what the solar panel looks like from the front.

 

Here I am testing first half panel outside in the sun. In weak sun through clouds the half panel is producing 9.31 volts. YAHOO! It works! Now all I had to do is build another one just like it.

 

I drilled a hole in the back of the panel near the top for the wires to exit. [...] Each solar panel in a solar power system needs a blocking diode in series with it to prevent the panel from discharging your batteries at night or during cloudy weather. [...] I added a polarized two-pin jones plug to the end of the panel wires.

 

Here is the finished product, producing 18.8 volts and 3.05 amps in the sun.

 

How much did it cost?

 

Not bad, though of course there's a lot of labor needed to actually build the thing, and you need the skills in the first place. Not a project for everybody, but those with the courage will certainly have a lot of fun.

 

This is just a quick overview of the project. If you want more, please visit Mike's website, which has a lot more details and more photos about how he built his inexpensive solar panels.