Pico Balloon Solar Panel
Introduction to Solar Cells
This video talks about how to choose solar cells and calculate their output at low sun angles. The minimum angle for transmission is important for winter flying when the maximum solar angle is very small. In fact, it goes to zero in northern Canada.
Building a Solar Panel
This video shows the process of building a solar panel. This is an earlier version of a panel. The use of solder paste is highly recommended instead of solder. Also take a look at the technique on the Traquito website the next section. That technique is simple and completely different than the one shown in the video.
The most popular and easiest panel to construct is a simply a flat panel of solar cells. Flat horizontal solar panels work well in the spring summer and fall but have difficulties in the winter in the northern hemisphere. In the winter the sun is at a very low angle and a flat solar panel will not get enough light to power the tracker for a large portion of the northern hemisphere. In mid-winter my tracker would not report if it was in Canada. Consequently, I did not hear from it for the entire month of January. People have used pyramid or cylindrical configurations to get around this problem.
The most common solar panel used is a flat panel made of 6 polycrystalline solar cells. In the winter in the northern hemisphere, the sun angle gets very low and sometime the balloon cannot be heard in northern locations because it does not get enough solar radiation to power the transmitter. Consequently, the balloon will not be heard for a few days, weeks or a month. This particular version of a flat solar collector was designed and built by Jim Janiak KD9UQB. Detailed instructions for building this panel are located here.
Traquito Solar Panel
Traquito provides a simple and inexpensive way to make a solar panel using an easily obtained printed circuit board. However, the cells are completely exposed and need more caution when transporting and launch. Details are located here
Here is a pyramid solar collector developed by Graham Collins VE3GTC that has been successful at powering a tracker at very low angle. Detailed instructions are included in this link. The instrutions describe placing the tracker in a foam box. This has been found to be unnecessary.
Here is an example of a solar panel was designed and built by Jim Janiak KD9UQB that works well in the winter. It has been proven to work on a flight that went 6 times around Antartica. Details for construction of this cylindrical panel are located here.