Three Hobbyist-Friendly Solar Cells
There are many solar cells out there, but cataloging them is beyond the scope of this book. Instead, I’ll describe three inexpensive cells you can easily buy.
Thin, flexible, and durable, this type of solar cell is often used for curved surfaces, such as an radio control (RC) plane’s wings. The cell in Figure 4.4 is from Jameco.com (P/N 227985).
FIGURE 4.4 Flexible-film solar cells are great for attaching to curved surfaces.
It measures about 1½”x2½” and is paper thin. It generates 3V and costs about $4.
Jameco has other cells from the same manufacturer, ranging in size up to 10x6 inches. Adafruit also has a flexible solar cell, a 6V model (P/N 1485) that measures 4”x8”.
Glass and Silicon
You’ll often find silicon solar cells faced in glass. I’m not sure if this is to weatherproof the cell, but it sure doesn’t help silicon solar cells’ extreme fragility. The one in Figure 4.5 is one of those solar walkway lights. Incidentally, you can get a ton of great components from one of those, ranging from rechargeable batteries to full-color light-emitting diodes (LEDs) and, yes, solar cells.
FIGURE 4.5 This solar cell came from a dismantled yard light.
However, you’ll encounter glass panels elsewhere. For instance, the $100 portable solar cell SunVolt (gomadic.com) is glass.
Plastic and Silicon
Most of the hobbyist solar panels you’ll encounter will consist of a board with one or more solar cells stuck to it and covered in clear resin. The Adafruit solar panel pictured in Figure 4.6 (P/N 417) is made up of 12 cells and delivers 6V at 3.7 watts and costs a reasonable $30. It’s pretty huge, about 7 inches on a side, but it would be great for larger projects.
FIGURE 4.6 The most durable type of solar cells are made of plastic and silicon.
I also have a smaller one, P/N YH30-18, from an unknown company. It’s roughly analogous to Jameco.com P/N 2136913. It’s about an inch long and has soldering points, and I’ve used it as a glorified light sensor in the past.