siliconmike said:
I'm building a battery charger to charge a single AA size NiMh/Cd using
a micro.
How to detect if the user inserted a rechargeable battery?
How to detect polarity of battery (if it is flat) ?
Mike
If a cell is totally "flat" then it may be impossible to reliably
determine the polarity via electrical means: it may be shorted or open.
If a cell is very low (say under 200mV), again it may be impossible
to reliably determine *correct* polarity, as misuse could have
reverse-charged the cell.
Naturally, if the cell is effectively open, it will not be possible
to electrically determine if it was inserted into the charger (use a
mechanical detector or mechanical means allowing insertion in only the
preferred direction).
Since you stated "rechargeable", there is no reliable way to
electrically determine if a fresh or new cell is a rechargeable or not.
The Eveready Renewal cells were alkaline rechargeable and had the
same electrical characteristics as non-rechargeable alkalines; both
similar to the carbon-zinc cells.
Have fun.
