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73 Amateur Radio - Free and Open Source Software
73 Amateur Radio - Free and Open Source Software
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73 Review bJ"Michael Bryce n 'BSl-'GE<br />
Numb8 11 on your FeedtMd< uorO<br />
Antennas West<br />
Solar Power Supply<br />
Good for even more than QRPf<br />
Antennas West<br />
Box 50062<br />
Provo, UT 84604<br />
801 -373-8425<br />
Price Class: $290 pl us $10 shipping<br />
In the past, generaling power from the sun<br />
was a hit or miss proposition. Most of the<br />
early solar electric pioneers used surpl us<br />
panels, with somewhat less than outstanding<br />
results. The technology and economics of<br />
converting energy 'rom the sun directly into<br />
electricity have improved rapidly.<br />
Antennas West's solar power supply is an<br />
excellent tust step in converting to solar<br />
power. The heart altha Antennas West solar<br />
module is the Sovonics P·101 panel. Sovonics<br />
is a foreru nner in amorphous sm.<br />
con, or " thin film" cells.<br />
Innovative Develo pment<br />
Until recently, most solar ce lls<br />
were made of crystalline silicon ,<br />
which has the regular lattice structure<br />
of a typical crystal-much like a<br />
crystal of salt or sugar. The amorphous,<br />
or irregular, structure considerabty increases<br />
the possibility that light will be absorbed,<br />
because the photons interact more<br />
with the amorphous structure. This means<br />
that an amcrpnccs cell can be made with less<br />
matenat than is needed with the more common<br />
crystalline silicon . Amorphous cells can<br />
be made only one micron thick , while crystalline<br />
silicon cells are typically 300 micron s<br />
thick. Amorphous silicon cells are applied to a<br />
substrate of stainless steel (as s c vcmcs<br />
does). Then the panel is encapsulated in Tedtar",<br />
a time-tested weather-. wea r-, and ultraviolet-resistant<br />
material.<br />
"Wiring the unit, panel to battery,<br />
is quite simple. Only four<br />
wires are used. "<br />
Sovonics produces their amorphous cell<br />
panels very much like newsprint. A roll of<br />
stainless steel is on one end 01 the proprietary<br />
continuous roll-to-roll process, and on the other<br />
end, out comes a 40 kilowan roll of solar<br />
cells. In this continuous process, layer after<br />
layer of semiconductor coating builds up a<br />
tandem cell 1/100 as thick as a human hair.<br />
The substrate is then CUl and installed into<br />
different Irames for their line of panels. This<br />
construction results in a panel that is flexible,<br />
lightweight. and unbreakable. However,<br />
Sovomcs does not stop here. In conventional<br />
solar panels, the interconnections between<br />
the cells have proven a real pain in the neck.<br />
Break one 01those interconnections, and the<br />
panel is dead. Sovonics has moved all the<br />
interconnections to the outer edge of the cells,<br />
avoiding the former pitlalls.<br />
sovonrcs also has added bridging diodes<br />
within the panel. By leeling along the back<br />
side 01 the panel . you can spot the diode<br />
" bumps." In the older crystalline cell panels, il<br />
you lose one cell, perhaps to thermal shOCk,<br />
the panel is useless. The bridging diodes will<br />
bypass the cell , allowing the panel to conlinue<br />
10 supply power. likewise, in a conventional<br />
cell, a shadow falling<br />
across a panel will shut down the<br />
entire panel. The Sovontcs panel<br />
will continue to work.<br />
Up to now, the great majority of<br />
solar panels on the market have<br />
been in glass. Glass is heavy, and<br />
no one wo uld arg ue that glass<br />
breaks. The Sovonics panels can be bent,<br />
shot with bullets, dropped, walked on, and<br />
generally beat up, and still work. Because 01<br />
the nature 01 amorphous silicon cells, they<br />
Photo A. Test setup of the entire Antennas<br />
West solar package. Note the difference between<br />
the P-201 and the corner of the Areo<br />
16-2000.<br />
54 73 Amateur Radio . June. 1989<br />
Photo B. The small charge controller that<br />
comes with the package is rated at eight<br />
Amps.<br />
Photo C. Current of 880 milliamps from a<br />
morning sun. Notice shadows under the array.<br />
The Sovonics P-201is in the foreground.