From my experience with these cells you need to heed the warning of "fragile!". Once you get the hang of how to handle them they work very well. In fact it wouldn't be a bad idea when unpacking if you find several (and you will) that are pretty broken up, play with them and see how easy it is to break them.
My first panel is below. It was a great success for about an hour. I was looking for the absolute cheapest route for glass. I ended up picking up a 60"x18" 1/8th" thick mirror, cutting it down and stripping the silver off the back. As mentioned, it worked great for about an hour. The heat from the sun and because the cells are so dark they absorb a lot of heat, it all added up to cracked glass. I was outside working while the panel was in the direct sun doing its thing and I hear "CRACK". I go look, a nice crack from the bottom almost all the way to the top. About 10 minutes later another - "CRACK". Okay, not a good idea to not use tempered glass. I have since ordered 1/4" tempered clear glass for about $44.00 a sheet for the size I need.
The other issue you'll run into with the cells is that until you get the technique down, they are somewhat difficult to solder to and the leads on many will be either partly disconnected or completely disconnected from the cell. I ran across an article on the net that kind of explained how to solder to these cells. On the back of the cell there are six spots to solder to. I simply load up the tip of my little 35watt soldering iron with solder and then drag the solder across the back of the spots one at a time. This seems to make a secure place for the leads from the other cell that I'll attach.
On the front of the cell is where the two leads are. To get them to stay put I use a razor blade to very lightly scratch the light tan material where the lead is supposed to be. You'll see silver under this material, that's enough scratching and you don't have to get all of the light tan material off, just enough to see the silver under it. I'm talking a hair line scratch will do just fine. Tin the lead with solder, let it cool and then lay it on the line on the cell where it's to be attached. Run your iron fairly quickly down the top of the lead, try not to hit the cell. It'll now stay in place. This works with leads that are completely off the cell and those that are only partly connected. I was able to salvage a good 30 or more cells that I would have not been able to use by doing this. The first picture below is of how the article said to do this which was to place the solder on the cell itself. I found that even with a low wattage iron that the heat was discoloring the cell. It didn't seem to affect the output but looks sloppy and actually was harder to get the lead to stay where I wanted it.
With this one I used the modified technique of scratching the cell and then tinning the lead, then putting the lead on the cell and running the iron down the lead fairly quickly. This of course looks much better and I had almost no discoloration of the cell. Output was exactly the same as un-damaged cells.
Out of my first box I should get six good panels. I already have my second box but haven't opened it yet. One of the other guys here suggested in a few message back about using a jig to keep all the cells in line - highly recommend his suggestion. Without the jig I pulled apart about four cells because I could see the cells were getting out of alignment. My panel is 2x18 cells. Can you imagine trying to keep 18 cells in a perfect line without a jig!
My panel puts out about 19volts and is a 40 watt panel. The two Arco M51 panels that I purchased off of eBay were around $110.00 each and though they work, they are in poor condition. The glass is shattered and they are beat up pretty bad. I also go lucky on the price. I haven't seen any go for that cheap in a while. This first panel with the new glass is going to cost around $88.00 when done. Now that I have made one, and I know what material I'll need for my second and so on, the price should fall to around $65.00~$70.00 a panel. That's only $1.75 per watt. Not to bad and I might even find some short cuts and be able to cut the price even more.
Good luck and enjoy.
