Dave Liquorice wrote:

On Tue, 31 Aug 2004 18:47:31 +0100, Alistair Riddell wrote:


varies with battery type but the main technique used is measuring
the current flowing through the battery with temperature sensing
often used as a backup.


NiCd and NiMH chargers are constant current, indeed the only battery
technology that I can think of that uses constant voltage charging is
Lead Acid...

Umm. Lithium uses conatnt curent/ voltage limited, the same as lead acid...

Detection of the rate of change of the terminal voltage is normally
used. Once the rate starts to fall the battery/cell is reaching fully
charged, the temperature will also start to rise more rapidly as the
supplied energy is no longer stored but dumped (for want of a better
expression).

Nickel chemistry uses peak detection. At some point in th1e charge the
voltage starts to FALL - that's time to stop charging or at least switch
to trickle charge.