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