Connecting the cells

Testing and Tabbing

As stated in the previous post, the next step is to ‘tab’ the cells. To do so, I had to check if the cells were working (had any voltage). Under the 60w bulbs in my room, each good cell got around 0.2 volts. I made sure each cell doesn’t have any cracks either, as I wanted the best cells to minimize damage later on.

I used the flux and applied it to the length of the two lines, this is where I was doing to connect both of tabbing wires. The tabbing wires are the short wires ~3mm in width. I cut them to slightly more than 16cm to compensate for the spacing between each cell.

After I fluxed, I applied some solder by heating the panel with the iron, then I applied the solder. Keep in mind that even though the cell is very fragile, it can withstand a lot of heat. I did this for the ends of each white line. After that, I applied the tab strips to the ends where I just applied the solder. I used a piece of cardboard to keep the strip down while slowly moving the iron along the wire. The animated gif below should provide better detail:


I repeated this for each cell. If a tab wire wasn’t quite sticking I removed the wire and applied solder underneath.


A good idea is to create a cardboard layout where you can align the cells. I used a right angle to draw lines along the length, then I measured out the width of each cell and the spacer. Since the cell was 15 cm by 8 cm and the cardboard had a thickness of 6mm, I measured 8cm, then 6mm, then 8cm and so on and so on…


To connect the cells together I applied flux to bottom of each cell and then I applied the solder. This step was important as it is very hard to solder without the initial blob of solder. After applying the solder I folded the tab from the previous cell down, then applied heat where the white squares are located. I did this for all cells, creating two rows of solar cells. I ended up with one cell on each row that did not have contacts on the bottom. It was necessary to add two strips there as well, as they were going to be used for the bus wires.

So what the heck are bus wires anyways?


Bus wires are the slightly thicker, wider tin wires that are used to connect strings of cells together. In my cell I used three bus wires, two for the + and – and one longer one for connecting the strings together.

Remember that the bus wires still need to connect strings in series, (+ to -) so make sure you rotate one of the strings!

Now that I connected all of my cells, it’s a good time to test them out. The 150w bulb in the bathroom was nice and provided 5-6v depending on how far away the panel was.

In the next post I will be showing you how to create a base for the panels. If you have any questions be sure to leave a comment!

Read more