A solar cell converts sunlight into electricity.
There is much information on the web on solar cells to find, but I do
not know much about us. There are even sites that describe how you can
make a solar cell. But that is something nice for once, but certainly
not an option when making large solar panels.
that I have found all have a voltage of about 0.5 volts but the
amperage is different every time. The mostly sold solar cell on ebay is
that of Evergreen. A number of suppliers on ebay claim that these cells
are not suitable for DIY, but I fortunately only read them after I had
already ordered :-) Of course, these providers have the right cells for
As I said my first set of cells were purchased on
first 100 cells I bought for the price of 180 dollars. These were
A-cells, according to the supplier cells with small defects. I have
chosen these because I do not know what the result of this project will
be so maybe it turns in a complete flop and then it is good I bought
the cheaper cells.
is a photo of the first packet cells. It is smaller than I had
expected. The cells are packaged in two "blocks" of 50 cells and 10
cells (bonus). It is well protected package and I do not believe that
the cells have suffered from the transportation. Furthermore,
there was a flux
pen, some (silver) tin and not unimportant bus wires.
The cells are 0.2 mm (yes 200 umeter) thick. This is very thin and
they are very fragile. A cell is 81 x 150 mm wide and weighs almost
nothing. It feels and looks very much like tin-plate. It is a (very
small) bit flexible and very fragile. It will break or crack very
Below a photo of a solar cell on top of 50 eurocents coin. It shows how
thin the cell is:
My first solar cells arrived yesterday (May 14,
2009). First I tried to solder a tab wire to the cell, but I came
trouble because my soldering iron is only 15 watts. Fine device for a
little simple electronics soldering, but not suitable for soldering of
solar cells. Today I borrowed a Weller at work and will try this
.... By the way; the first cell is broken in little pieces during the
soldering. So more details on the soldering.
In my work
I spoke with a colleague who does the soldering for all projects. In
beginning it didn't became all much clearer, but that was partly
because I do
not know exactly what I wanted. Eventually it became more clear to me
and now I
think I understand pretty well what to do. First this: I come from the
era. Most know it, but some may not. S-39 is a flux, but it is very
acid. It is not only unhealthy to use, but everything what you soldered
gets reduced in life expectancy. It eats everything away everything in
time. Of course I am
familiar with solder with flux in it. I believe that we formerly called
resin, but the details I do not know. In addition, since some time
lead-free solder is used. Not for test projects, but within our company
for what is sold to customers. This is because lead is bad for nature
and has become forbidden to use.
For my project I can still use lead solder (even if it is
bad for nature and a bit for me). Let me make one thing clear, I am
building solar panels because I like and hope that a "reasonable"
investment, but I'm certainly not a green guy. The solder what
came with my
package from ebay also got silver, but only 0.7%. It is in this case
(as I understood from my colleagues) a lead replacement for an alloy to
make. The silver in this tin does not cause less electical resistance
or a more pure connection. This is possible with silver tin, but
then you are talking about a much
higher content of silver and solder that will be much more expensive.
By the way, this tin (with high silver percentage) is virtually not
available for the normal man. The disadvantage of the supplied
solder is that a slightly higher temperature was needed, so I will
stick to lead solder.
took a while before I realized how to get the flux out of the pen
;-) You should
press the point a few times and then it will start to run. The flux is
fine. As I have said I have little experience with soldering so I just
started. The aim is to solder a tabwire of 15 cm (8 cm in front +
rear at about
7 cm) to the front of the cell. Then this wire is soldered on the back
of the next
cell to create a series connection.
Above a photo of a cell with some tabwires. At the right is the result.
me say that this result was only achieved after many trials, but I am
satisfied with it.
tabwire is a flat wire (of what I do
not know, copper or something) which already contains (silver) solder.
idea is that the flux is put on the cell flux (on the track where
the tabwire is to be soldered) and the solder the tabwire onto the
cell. This will work fine in production environments (factories), but I
not so successful. I needed a lot more solder to create a good
connection. The first thing I've tried is extra solder on the tabwire
to and then the cell soldering. That was not good, but mainly because I
did not know how to use the flux pen. In addition I tried that method
with my own simple
bolt, so this method might work fine with better equipment. After this
trial I tried to put solder to the track of the cell and then
solder the tabwire to it. First, flux it
and then put solder it. Then solder the tabwire on it. That worked
well, but a number of findings. I used a glass substrate, which
absorbed the heat. So for the tabwire soldering I had a 400 degrees
setting on the bolt. While the tinning of the cell only
needs 360. Indeed, if I used 400 then the track (which is like a
white silver appearance) located on the cell is burnt away, and then
you have a
problem. But this worked well and I have the first cell made so looks
like a reasonable method of working.
As I went on with my project, it became increasingly easier and
ultimately I did the following: I have made a toolbar. See the pilot
for details thereof. At this bar I place a number of cells. The bolt is
at a temperature of 350 degrees and never higher.
In my left hand solder (I use solder with flux in it) and in the right
soldering iron. Then I go from right to left and I place solder on the
cells. I leave a lot of solder behind and it doesn't look really nice,
but it is fast and ultimately it is very good. In the beginning I put
on the cell before I started but I stopped that because it is not
necessary and it takes time to do, and I don't know if this flux
needs cleaning afterwards. If both tracks are with solder I
will place the tabwires. I start at about 1 cm from the end of the
tabwire and solder it
on the cell. Sometimes I do a little solder to the bolt so it
starts to flow easier. If the wire is stuck I pull it and hold it just
above the cell. Then I pull the bolt slowly over the wire from right to
left starting at about 1 cm from the side. If there is enough solder on
the cell is then you can process without additional solder.
In the beginning I tried to put the solder on the cell as beautiful and
possible but that is not necessary and it only costs additional time
and effort. After soldering the tabwire to the cell
eerything smooths out is beautiful to see.