Digital watches on plain Lithium cells last years - the Solars will crap out after time since their storage batteries do not last forever.
Although the idea of never having to replace a battery may seem on paper to be appealing - and I've been tempted myself -
the problem is that the "accumulator" of the solar generated electricity is actually a "rechargable battery" - which unfortunately does not last forever and will eventually need replacement.
I'm not sure of the technology used for the storage/rechargable battery -
but we all know NiCd's are terrible - heaven forbid it's one of those.
Lithium rechargables are supposed to be good - but really meant for high drain applications - I had 2 Li rechargable batteries for my Canon digicam - and after 3 years of cycling usage they both gave up the ghost.....
NiMH seems like a good technology - but again for high drain and I'm not sure how they react on slow trickle drain/charge - but even they only claim 500-1000 cycles of charge/discharge - at 1 cycle/day that's only 1+ to less than 3 years - OK maybe it's not 1 cycle/day - 1 cycle/2days average?
still = less than 3-5.5 years - that's still not "forever".
Personally I would prefer a regular lithium powered watch.
On Casio G-Shock Tough-Solars the storage battery is a Casio type CTL1616
(I suspect this is just Casio's own designation for the lithium CR1616 - which is normally used as a backup battery.) -
Seems like if the watch does not get enough bright light - it keeps using the back-up battery - and the watch dies or malfunctions after a few years - much less than one would expect - as these threads seem to indicate -
G-shock Tough solar problem
Casio Atomic Solar watch - opinions?
Anybody played with these Casio watches?
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Vincent
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