"DaveC" wrote in message
al.net...
On Wed, 12 Jan 2005 12:46:42 -0800, harrogate2 wrote
(in article ):

Either way they are part of the charge sense or charging circuit. If
the battery has three contacts, then you have +ve out, -ve out, and
charge probably common to -ve. The diodes ensure polarity, the
resistors control the charge current, simple as that.

So the diode specs aren't really important (as long as they handle the
forward charge current, that is)?


Yes, if they are passing the charge current, but given the new info you've
provided, they aren't...

But why 2 diodes and 2 resistors, if the designers weren't trying to get
the
v. drop precise?

And why are there 2 resistors rather than 1 360-ohm one?
--

If the resistor really is 360 Ohms then the resistor and diode are not
passing the charge current, the resistor value is far too high for an approx
120mA charge current a standard C cell expects. Even with a 12V charger,
(very unlikely for a 2.4V battery pack) there would only be a 33mA charge
current through a 360Ohm resistor, which would take over 50 Hours to charge!

You'd need a 43V charger to give a 120mA charge current through a 360Ohm
resistor, and that's ignoring the drop across the NiCads and diodes.

The diodes and resistor have to be part of the sense circuit, so you'll need
to do a little digging into how the charger works.

Dave