Part 2 of our solar power tutorials. Most DIY homemade solar cells follow the same design patterns as their commercial counterparts. When constructing your DIY solar panels for home use there are two generally accepted approaches to cell size, and the linking structure of the individual PV cells within the panel.

1. Solar Panel Size

The typical solar panel contains 36 PV cells, with four rows or strings of 9 cells each. However, if you prefer to use larger panels to minimise the construction of the housing for the components, a panel comprising 48 PV cells in four rows of 12 is also an option. Really, you can tailor your panels to any size or configuration you want, but just be wary that longer strings bring more opportunities for bad connections, breaks or problems due to faulty cells.

2. String or Zig-Zag Connections

The second option is whether you want to create linier strings of PV cells or to connect them in a snaking fashion across the backboard. The basis behind the latter design is that there is no wasted wire connecting the strings. The effect is essentially the same, however we’ve only ever used straight line connections because frankly its easier to keep a handle on during construction and is less likely to lead to errors. Both options are set out in the diagram below.

3.  Types of PV Cells

In terms of the PV cells that can be used in solar panel designs, its really a case of anything goes. Some people prefer the rectangular 3×6′ cells which can be affixed quite close together, others prefer the 4′ or 5′ squares. From the perspective of shape, either variety is fine and it really comes down to personal choice.

A more relevant consideration is the quality and capacity of the cells being used. As discussed in part 2 of our solar power tutorials, most PV cells can generate 0.55 volts, but have varying amps, and it is these attributes which ultimately determine the number of watts a panel will be capable of producing.

Some sites will advocate finding damaged or second hand PV cells for free or cheaply. There are some sources of quality cheap cells, but we generally feel that the problems second hand or damaged PV cells can create far outweigh the financial benefit that might be derived from using them. Cells which don’t operate optimally can impact on your whole exchange, which in turn reduces the power generated by the entire array. It also makes combining the cells into strings on your backboard more labour intensive as it is better to group cells which generate approximately the same level of power.

Cells of reasonable quality can be found on sites like ebay, or purchased online, and if we’re going to invest our own time into our DIY solar power project its better to know we’ll be getting some bang for our buck once everything is up and running. Even using cells purchased at retail prices can still equate to significant savings on our domestic solar array, which can easily run to prices between $10,000 and $20,000 if professionally installed.

Next, we’re going to look at our DIY off-gridsolar power components.