Introduction: Building a Solar Panel From Cells

By
About: I'm a Mechanical Engineer who has been a part of this community for over 10 years! My interests have evolved over time, and now center around 3D printing.
A goal of mine is to have a constant, reliable, free, clean, source of flammable gas at my house.  This is proving to be quite a challenge.  I have been breaking water into hydrogen and oxygen for quite some time, so that is the route I chose.

In this Instructable I will show you how I constructed small solar panels for use in my larger Solar Hydrogen Generation project that I will post later.  This Instructable will focus solely on how I assembled cells purchased online into functional panels.

The steps in this Instructable will include the following:
  • Step 1 - Materials
  • Step 2 - Building Part 1 - Soldering Leads to the Front Side
  • Step 3 - Building Part 2 - Soldering Leads to the Back Side
  • Step 4 - Building Part 3 - Final Assembly
  • Step 5 - Conclusion
*This Instructable involves the use of power tools.  As with any project, be smart.

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Thanks to everyone who voted for me, and the judges of the 2011 Green Living and Technology Contest!!  I am honored to have won second prize, thanks!!

Step 1: Materials Needed

The materials I used to build my solar panels are as follows:
  • Solar Cells - I purchased mine from Electronic Goldmine.  They often have sales on different cells.  I chose some cells that were about 4"x4" (4 inches wide by 4 inches tall) that give off about 0.5 volts.  I don't remember the amperage of the cells, but I remember it being fairly high, which is why I chose them, as electrolysis works well with low voltage and high current.
              The Electronic Goldmine site is here: http://www.goldmine-elec.com/
  • Solar Cell Ribbon.  I also bought this from Electronic Goldmine.  It is very thin, flat wire that is great for soldering to the solar cells.  You can get away with using thin wire though.
  • Picture Frames - I bought the biggest ones available at the dollar store, which held 8.5"x11" pictures, the size of copy paper.  I used two for this project to fit all my cells.
  • Foam Rubber Sheet - I bought this at the craft store to use in various projects.  It is available in multiple thicknesses for less than a dollar for a decent sized sheet.  I meant for this to help keep moisture away from the cells, which you will see later.
  • Plywood - I am using thin, 1/8" (one-eighth of an inch) thick plywood that I salvaged from some wooden pallets.
  • Matching Nuts and Bolts - I am using stainless steel nuts and bolts that can be found at any home improvement store.  I chose to use stainless steel because they will be out in potentially rough weather, and I want them to hold up.

You will also need some tools, as following:
  • Soldering Iron and Solder
  • Drill
  • Jigsaw or other tool to cut plywood
  • Dremel rotary tool - optional but helpful
  • Sharp knife, screw drivers, various hand tools

Step 2: Building Part 1 - Soldering Leads to the Front Side

The solar cells came from the box wrapped in loads of bubble wrap, and a small directions sheet on how to solder wires or leads to the cells.  The directions helped a lot and when followed correctly, it worked out well.  Different cells may have different soldering procedures.

I chose to start the soldering of tabs/leads with the side of the cells that will face the sun, as it seemed more challenging.  To do this on my cells, the first thing I did was to use a knife to scratch off some of the white protective coating where the leads should be soldered, like my directions indicated (Pic 1).  I believe the side that is to face the sun will be the postive (anode) side.

Next, after my soldering iron was hot, I heated some solder to stick to the ribbon wire that I bought to solder to the cells.  With the solder on the wire, I then placed it on the area where I had just removed the white protective coating, and by pressing the wire to the solar cell with my soldering iron, soldered the two together.  I tried to explain this in the pictures as best I could, but a person can only hold so many different things while taking pictures.
     A few things to point out are that my directions recommended using a variable temperature soldering iron on a low setting, which I didn't bother with because I don't have one.  My directions also suggested to hold the wire in place to the cell, and then apply the solder and heat to the both, which I tried, but found that applying solder to the wire first worked better.

Finally, I cut the solar cell ribbon wire a small length after the edge of the cell, so that I could switch to different, more plentiful wire, to save the thin wire for more soldering that had to be done.

Step 3: Building Part 2 - Soldering Leads to the Back Side

On the back side of the solar cells, the side not facing the sun, the soldering process was easier because there was no white coating to be scraped off.  Instead, there were small areas where leads are meant to be soldered to.

To solder leads to the back of the cells, I again applied solder to the solar cell ribbon wire, and then held it to the rectangular area where leads are meant to be soldered to, and pressed the wire down to the rectangle with the soldering iron.

I then snipped the solar cell ribbon wire short like the other lead, to be able to use less of the solar cell wire.

I finally soldered some wires to the solar cell wire attached to the cells, and put some hot glue over the space where the cell ends and the ribbon wire begins, to insulate and strengthen it.

I tested the output of each cell with a multimeter to see what I was getting.  I also connected some cells up to LEDs and a few small motors to test my output.  These tests were done to determine how I should combine the cells in series and parallel to get the right amount of volts and amperage for my application.  I ended up deciding to connect them all in series, as my output was fairly disappointing.

At this point in the process I started to have problems with cells breaking, as they are literally paper thin, and break very very easily.  I managed to put some back together, making sure to align all the thin white lines on the front side of the cells together and taping/hot gluing them in place.

Step 4: Building Part 3 - Final Assembly

So now the solar cells have wires soldered to them, and we have decided on our combination of series and parallel cells to suit our needs.  Now what's left is finding some enclosure to protect the cells while allowing them to be protected from the weather but still receive sunlight.  I chose to use picture frames as the main element here.

I opened up the picture frames and bent back the small pieces of metal holding the cardboard backing in place.  Because these panels will be outside, cardboard won't do.

I used duct tape to lightly secure each cell to the glass of the picture frame where I wanted it, making it much easier to work with.

I used my Dremel rotary tool to cut a small notch in the side of the wooden picture frame so that the wires would have a place to leave the panel.

I cut a piece of plywood from a reclaimed pallet the same dimensions as my picture frame.  I believe the overall dimensions of the frame were 9.5"x12".  I then cut a section of foam rubber sheet to the same dimensions.

I clamped the frame and plywood together with the foam rubber sheet in the middle and drilled four holes in the picture frames so that the would assembly could be bolted together, sandwiching the foam like a gasket and protecting the cells.  When I looked at the frames, it seemed like they had small metal brackets at the corners holding them together, so I made sure not to drill holes in the corners of the frames, but a few inches to the sides. 

I used stainless steel nuts and bolts to hold it all together, and sealed the opening where the wires exited the panel with hot glue because the opening seemed too big, and would let moisture and other potentially damaging things in. 

Step 5: Conclusion

The panels are now fully assembled and fuctional.  They are small enough to be moved, and I hope that I will be able to get a small bit of hydrogen out of them when the final project is done.  I hope this Instructable was helpful in some way.  I will point out that during the total process, I ended up breaking nearly all of the cells and trying to repair them in some way.  In the future, I believe I will only buy glass-plated cells that are sturdier and have leads already soldered to them.

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Thanks for reading.

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