My ir perpetual solar charger.

[onthecuttingedge2005]

use Germanium Solar cells, 40 to 50% efficient.

[the_big_m_in_ok]

use Germanium Solar cells, 40 to 50% efficient.

You're right.  Germanium and Gallium-Arsenide substrate cells are just about the best available.  If they're available in your area, and you can afford them, then they're the ones for the job.

The most efficient Radio Shack cells are .55VDC @ .5A, and the cell is around 1.25-1.5 sq. in.   $4.99/ea. without tax.   I think these cells are one or the other above.  Soldering on them would be a pain-in-the-butt, though.

--Lee

[the_big_m_in_ok]

...I think these cells are one or the other above.  Soldering on them would be a pain-in-the-butt, though.
--Lee

I tried super-gluing connections to the cells and it was too difficult to control positioning of the leads and avoiding glue messing up things like fingers and the work surface.  (Soldering may not be a good idea in an apartment with thin walls and smoke detectors installed.)

The high efficiency cells were also too brittle to work with.  I'll use the Radio Shack solar "panels" instead.  $14.99 ea. before taxes.

--Lee