DIY Solar Panel

Step 5 Linking the cells

This can get a bit tricky, but once you get the hang of it, can be done fast enough. First, some technical notes: In order to get higher voltage, you need to connect two cells in series. This means that the negative part of the first connects to the positive part of the second. As you continue to add more cells in series, you will get a higher voltage from side to side on your solar strip. This is all good, but if your cells are small-ish, they won't generate much amperage. So even if you have a high voltage, you probably won't be able to give it any load (probably will hardly light an LED). In order to get higher amperage through the circuit, you need to connect cells in parallel (positive side to positive side, negative side to negative side). When you do this, make sure the positive and negative leads (copper mesh in this case) don't short themselves out.
I found that the best way to connect between two cells was to use hot glue and some conductive mesh. The mesh is good since it allows light to come through it, and we all love glue guns. So all you need to do is glue the mesh onto the solar cell surface. Its always better to have a longer strip of mesh on the surface, with a big enough shared surface space between the two. Always check with a multimeter that there is connectivity, and that there is voltage coming through. Its a bummer later to try and figure out where the problem is.

Comments

[HRobinson]

Just joined and just found this posting ... you guys have some interesting stuff on this website! ... please excuse my ignorance but doesn't the glue act as an insulator or is there a conductive glue we should be using?

[dagenius]

You don't actually want it to conduct--you already have the conductive ink, and existing connections to do that. If the cells were encased in conductive glue, then they wouldn't have any output (short circuit).

[j1432]

One thing to be aware of is that by stinging the cells like this you are increasing your voltage but not necessarily doing yourself a favor. The current of the string will be limited to what the smallest cell can put out. It would be best to string together cells of similar size.

[pyrogoth]

there is actually a way around this, its really simple instead of having a larg cell with like 2 smaller cells after it u can have the 2 smaller cells parralel to each other after the larger. or you could combine the 2 cells together by bridgeing the sides together. top left:the orignal series top right: smaller circuits in parallel bottom left: parallel and bridged at the negitive leads, might wana brigde the positive sides also(all this seems kinda sense-less but might improve performance.)

[pwnz32]

The current's limited by the size of the smallest cell?

[j1432]

Yep. I tried to piece together some mismatched cells like this once and found this out the hard way. Here's a neat thing to try sometime: Take a magnifying lens and focus the sun onto a tiny solar cell. I did that once with this cell: http://www.solarbotics.com/products/scpd/ which puts out about 2 mA with full sun. As I recall, I got it up to about 250 millamps. Not bad. Of course, I didn't do that for long because I was afraid of damaging the plastic encapsulating the cell.

[oldandintheway]

Saw a thang on the science channel awhile back and smart guys are magnifying solar cells in space. Site in your ray gun the plan is to beam back the amped up juice by way of microwaves.

[blindsided]

Yes for solar cells generally a larger cell yields more current

[thearchitect]

Great instructable!.. A few questions, though: 1. Instead of a conductive mesh, can we use thin single conductive cables? 2. Would it be a problem to connect them on the tracks you printed with silver pen? 3. Can you solder on silver pen tracks? 4. Did you try cutting solar cells with glass cutter? Is it possible to trim them into nicer shapes?