>
> You don't need a regulator, the batteries will do that for you.

Only until they blow up or blork out thier innards from overcharging.  I'd
have to disagree, a regulator is a good idea when charging batteries.


Now, NiMH's are good batteries but they require complex charging circuits to
get any long life out of them.  Lead acid cells, OTOH, are usually cheap,
rugged, and forgiving about charging.  You might get away with a very simple
solution with a lead-acid cell, a simple three terminal voltage regulator,
and a solar cell that provides enough extra voltage to overcome the
regulator's drop voltage.  Even a resistor-zener regulator might do for such
a small system.  These are cheap Radio Shack parts, crude and inefficient.
But unlike most solar systems, you've got power to waste if your load is
microamps and your cells produce milliamps.

Any battery will have a shorter life if it is not charged properly, the
question is how much effort and $$ do you spend on a better charger versus
replacing a battery every so often.  Most any battery that is overcharged
consistently will clue you in on it's inner feelings about this subject in a
dramatic way.

A buddy of mine has lived with a solar electric system for his house for 17
years.  Early on, we had used golf  cart batteries or old car batteries and
a hacked homemade charge controller which was far from ideal.  He replaced
batteries every two years.  In recent years he bought a better charge
controller, and batteries haven't been replaced in 4 years, so far.

-Lawrence

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