>
>
> > :: Sort of. It takes less hardware to mount an array of many panels
> > :: that way.
>

For small arrays. For large arrays where you have more freedom of
positioning and mounting, it should be about the same either way.



> 2.5 years. My favorite battery chemistry is NiMH (used in the TOYOTA
> PRIUS), as its operating lifetime is 5+yrs, but also more expensive than
> lead-acid types.  .
>

For whole of life cost per cycle you may find LiFePO4 of great interest -
much more so than LiPo.

I have come to dislike NimH in the sort of applications that I have used
them in extensively (some hundreds of thousands) in recent years. When
energy source is copious and steady and environment is reasonably benign,
then NimH may do well. In small solar systems 'in the field' LiPo and
LiFePO4 are much easier to manage well. NimH does not well tolerate the
sort of temperatures  that small portable equipment may experience
(especially if solar charged with internal panels) and ALL the more usual
end of charge indicators are badly confounded by a variable energy feed and
high and variable temperatures.

OLPC report 3,000 cycles of use for both NimH and LiFePO4. They take about
10% of capacity off both ends of NimH usual energy availability curve to
achieve this. (ie battery is rated at 80% of nominal capacity) (ie
terminate charge at lower than usual voltage, terminate discharge at higher
than usual voltage.) OLPC members on this list may wish to comment on this.



           Russell
--=20
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