On Saturday 13 October 2001 06:53 am, Wojciech Zabolotny wrote:

> R2 measures the battery charge current, and R3,C3 form the lowpass filter
> for mean current measurement.
> R4,R5 and T2 create the battery discharge system.
> So one needs two A/D pins and two digital pins for each battery, and one
> PWM output for all batteries (well it is possible to use two PWM output to
> charge different size batteries simultaneously).

Well, your sense resistor R3 has to be very small for efficiency, so the
voltage will be very low (that is, if you want to limit losses in this part
of the circuit to 5%, then the voltage across the resistor will be roughly
60mV).

Unfortunately, 60mV is only about a third of the minimum PIC A/D +VRef of 2V.
My guess is that you'll want to amplify this sense voltage.

--
Ned Konz
currently: Stanwood, WA
email:     ned@bike-nomad.com
homepage:  http://bike-nomad.com

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