In article , "Joel Kolstad"
writes:

Watson A.Name "Watt Sun - the Dark Remover" wrote:
Also the currewnt outputdepends somewhat on the latitude you're at. You
won't get all that current at the arctic circle.

He might actually have a better chance there during the periods when the sun
never sets than at, e.g., the equator... solar cells are noticably more
efficient when they're keep cold, which is typically a lot earier to do in
the arctic than at the equator!

Ahem, Joel, consider the location of "the land of the midnight sun..."

:-)

Ackshully, based on a little bit of experience on Solar One, the
first (of two) experimental 50 MWe solar plant in Barstow, CA,
(in the middle desert of California with not much else), sunlight
has a considerable variance in energy over the course of a day.
A combined buck-boost switching power supply would be a
consideration for reliable solar cell charging of a secondary
battery during daylight. There are several different ICs just for
the purpose of wide-voltage-range inputs from National, Linear,
and Maxim along with application notes from all three.

Roy Lewallen hit the subject nail on the head in saying, correctly,
that solar cells behave more as constant-current sources than
constant-voltage (as batteries are) sources. Those who care to
test that will find out from connecting a fixed resistor to solar cell
outputs and measuring the voltage during the course of daylight,
especially the differences between clear and cloudy skies.

Solar One was a boiler system, over 500 independent mirrors were
used as a giant reflector array to focus sunlight on a central boiler
made from the same stainless-steel-like tubing used in rocket engine
bell structures. Rocketdyne Division of Rockwell International was
the subcontractor to MacDonnell-Douglas that made the boiler and
the underground steam-heat storage system of Solar One. The peak
daylight energy was in excess of 100 MWe equivalent but the extra
heat had to be stored overnight for the steam-turbine-powered
generators to run 24/7. Rocketdyne, now purchased by Boeing,
made the Space Shuttle Main Engines. Rocket engine bells
are made from tubing to circulate fuel before entering combustion.
That pre-warms the fuel as well as cooling down the tail of the
engine's output.

Not exactly what a QRP operator would need... :-)

Len Anderson
retired (from regular hours) electronic engineer person