On Thu, 29 Sep 2005 07:19:14 +0100, John Beardmore wrote:

I think a truly smart
charger would require smart batteries that have a very small amount
flash RAM. That would allow the charger to write information to the
batteries identifying their last couple of charge cycles, with
date/time info. as well as design capacity and recent capacity.
That would allow the chargers to easily handle temporary loss A.C.
power during the charger cycle and also let you know when it might
be approaching the time to replace the batteries.

I would have thought the actual performance of the cell would be the
better indicator for determining replacement.

It would, if you can make some assumptions. But as Ian pointed
out (using barcodes) if you're not restricted to a single charger
that can compile a history, how would a different charger seeing a
cell for the first time know what I referred to as the "design
capacity" of the cells? While it has been almost a year since I
bought NiMH AAs having less than 2,500 mah capacities, only a few
months ago I bought a radio that for some odd reason was supplied
with four brand new 1,100 mah NiMH cells. I wouldn't want to use
them in a camera, but they do an adequate job in the radio. The
"smart" charger would need some way to differentiate between these
batteries and 2,500 mah batteries that through use now only have 1/2
their "design capacities" remaining. While it's true that they'd
also be adequate for use in the radio, I'm not aware of any charger
smart enough to know what kind of device the batteries would be used
in. For that it would be beneficial if in addition to the chargers,
we also have "smart" users.