Measurement of cell voltages within a battery
Gerhard Fiedler email (remove spam text)
Michael Rigby-Jones wrote:
> I'm trying to design a battery monitor circuit that needs to know
> individual cell voltage to a good level of precision (+- 5mv would be
> great, 10mv acceptable) over a temperature range of 10-90 degrees C. A
> PIC will be digitizing the voltages with it's 10bit ADC. Cells are
> nominaly 3-4 volts, and there could be up to 6 of them in series in a
> battery. Now the killer, it must to be as cheap as possible.
How about one PIC per cell? If the cells have >3V, that should be good
enough. And could be cheap PICs... the only thing you need is a 10-bit ADC,
a GPIO (and an internal oscillator).
Communication (one-way) could be done with optos or with some kind of
digital level shifter, which probably isn't too difficult to do with a
couple resistors and a schmitt-trigger gate or so.
The PIC that's connected to the grounded cell measures that cell and
receives the comms from the others and presents the result to the outside
In reply to: <23075D38FE1C8144847DFAECA3565F2704E54F55@pai-smx-01.europe.bkhm.net>
See also: www.piclist.com/techref/power/batterys.htm?key=battery
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