In october 2002 i decided to buy a 15watt solar panel as all earlier attempts to make one had failed or almost failed there was some limited sucess but i will come to that later. 15w at 12v may not sound much but its 1 amp in full sunshine and my primary aim is to keep a 100ah battery charged ( im only working on a small scale here ) with daily use to run lights in my workshop. After buying the panel i was really pleased with its performance and this has just got to be the ultimate way to produce clean green juice but somehow the price just does not warrant the return from such an excellent idea. I dont think i will be rushing to buy another but i am working on making solar cells ( with a little help from my friends ) and will keep you posted on the results.
Above you can see the 15w pv in the workshop window and it worked fine there but was shaded in the afternoon sun as it passed west so i moved to the roof top of the house which is south facing and perfect for max output from pvs.
After hours of searching the web to find out what solar cells are made from and how they work i was convinced that there must be a easy way to make something that worked. With each picture there is a brief description as to why i tried what i did other wise you would be under the impression that i am plain bonkers.
This funny looking thing was my first cell.A foil pie tray was used as these conduct and would hold my concoction! Next i put the kettle for a cuppa and used the remaing boiling water to mix the with the salt.I added some blue food colouring to darken the mix in the hope of it absorbing photons.This took more than a week to dry in the middle of summer, once it had dried out i was left with a tray full of wonderful salt crystals just as i had wanted.A single copper strand was coiled and placed on top to form the remaining electrode ( the tray was the other electrode ).When i placed it the light with the meter connected i had half a volt WOW! But i soon noticed that this half a volt was still there when the light wasnt. I had made a battery cell not a solar cell and the reason i tried salt crystals you might wonder was because there crystalline and i read not too unsimiliar to silicon crystals.
Try again and this was my next cell, trying to get closer to the real thing i mxed some bathroom silicon sealant with a little shoe polish on a metal disk then placed a metal strip across the top for the other electrode. After placing the metal strip on the mix i checked the cell was not shorted with a meter then allowed it to cure overnight. Once cured i tested it.......zilch......zero.......nothing in fact this cell was one hell of a good insulater!!!!
Still searching for anything thats composed of sillicon i found a roll of fibreglas matt in the workshop. Using an empty cd case i lined one side with foil cut a square of the glass matt placed it on the foil and finally a foil strip across the top. About 2mv was present so i added a few drops of iodine to make it a wet cell and 5mv with no light but this jumped to 7.3mv when exposed to light. At last something that responds to light but i need more power than that A LOT MORE.
More silicon things and a small sheet of glass kept over from broken picture frame was the next victim in my quest for a homemade pv. Yes one side foil and a strip of foil on the other this responded to light but only just and at .13mv i decided that more research was needed to further my understanding of solar cells.
Oh i see a silicon solar cell is 2 pieces of silicon one being positive and the other negative and when this junction is hit by light the juice happens. How on earth do i make one of them junctions without an electron microscope to see what charatistics the silicon has? Hang on a minute thats a diode and theres glass diodes on most pcbs in the form of signal diodes and zener voltage reference diodes Mmmmmm where did i put those scrap boards that i refused to throw out. Got them and removed as many as possible without being driven insane. About 10 or so signal and zeners were removed and then all the signal diodes were wired in Parallel and the same for the zeners. The signal diodes worked but only 250mv oh well were getting there but the zener diodes gave .310 of a volt with just a torch and .4 of a volt @ 20 micro amps in strong sun light. I got something in the end but it would take thousands of these zeners and lots of hours removing them from boards but im still thinking.