On Monday, August 15, 2011 1:19:07 PM UTC-7, Dave Platt wrote:

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.

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,

It probably suffices to use a ten-hour timer with an AC outlet .
Plug your batteries into the charger, plug the charger into the outlet,
and hit the button. Ten hours later, the battery is charged and
the charger is off.