Two benign battery technologies: zinc-air and lead acid.  The latter fits
because it is so easily recyled.  But there is a new development that
improves life expectancy 66% or more.  It is called the Can-PULSE System.  It
uses high frequency, high current pulses during charging to break down
hardened, crystalline lead sulfate.   Information is available at
<www.canadus.com>.  I have no personal interest, just intrigued by a
constructive approach to conservation.  Also it another blow against the
misbegotten anti-lead bugaboo.

Harvey Miller