"Mark James Boyd" wrote in message
news:40140af4$1@darkstar...
From what I can gather, the low-power transponders are 400mA
and encoder 200mA at about 12 volts.

The microfilm superthin solar panels about 1 foot square (12" by 12")
advertise 600mA at about 12 volts.

Sadly, the solar panels in my experience don't put out rated power
on typical days, with less than ideal sun angles (maybe really only
putting out 25%).

Also, I suspect transponders underrate their power consumption,
and if flown in high jet traffic areas (where they get
pinged by ATC and the jets), probably consume quite a bit more.

So really one might be looking at 8 square feet of solar
array just for a transponder! Maybe a little hard to
implement on a glider without using the wing surfaces,
and the caveats that entails...

Well, it was a nice thought...

That's today, tomorrow may well be different.

http://www.lbl.gov/Science-Articles/...olarcells.html

http://www.scienceagogo.com/news/200...runc_sys.shtml

or this

http://www.californiasolarcenter.org...0030128-6.html

Perhaps someday be able to shoot a top coat that will take care of keeping
the batteries up. There's work being done at the nanotech level to make
these much more efficient. Imagine the diversity of applications, roofing
materials, car finishes, clothing, tents, aircraft, boats, etc.

Frank Whiteley
Colorado