In article ,
gregz wrote:

OTOH,the B&D Dustbuster I had was designed to stay on the charger when not
in use,and it lasted 10 years before I had to have another NiCd pack
installed. that new pack lasted almost as long.
I've seen NiCds listed at DigiKey specifically intended for staying on the
trickle charger when not in use.

Never got any long use like that with several I used. My current red devil
extreme, I only charge it once in a while, and is doing great so far. It is
never without some reserve power left? One Dustbusters I converted to NiMH,
and was a disaster.

The DustBusters I have had (which have two removable battery inserts,
which I believe use sub-C cells) have not survived well. A year or
two sitting on the trickle-charger (as designed) and the NiCd
batteries are toast.

I've been thinking seriously about tearing it open, and replacing
whatever simple fixed-resistor slow-charge circuit it has with a
proper faster-charge-and-real-cutoff circuit of some sort. I'd have
to replace the wall wart, most likely, to get a decent charging
current.

Seems like there ought to be a single-IC solution available today...
and if not, something simple with a PIC or other micro to switch from
full-charge to "off most of the time, very brief current burst every
few minutes to cancel out self-discharge" should be able to do it well
enough.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
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