Building a NiCd Charger

[kl1k]

I'm looking to build a NiCd charger to charge 2 or 4 1.2V NiCd's

The only circuit I've come across is for a 9V battery
(http://www.uoguelph.ca/~antoon/circ/nicd.htm)

Has anyone tried to convert this to change 2 or 4 cells. Or can anyone
point me to another free circuit.

 

[PeteS]

As noted above, Microchip (and others - Maxim and TI spring to mind)
make charge controllers for multiple battery chemistries, NiCd
included.

Having once spent a while in the black hole of NiCd analysis, I would
caution you to read carefully the charge permitted for the particular
cells you wish to charge, for they are not all created equally. Some
permit fast and rapid charge, others only permit standard charge
(Standard is normally C/10 for ~14 hours, Fast C/3 for 4.5 hours, Rapid
2C for 1 hour although these vary among manufacturers).

In addition, you should consider a charge conditioner to get around the
memory effect (that manufacturers will tout as having been solved, but
they really haven't) to maximise the life of the cells. Takes a little
longer, but saves a lot in the long run.

Cheers
PeteS