If you run the 10 bit A2D with external reference voltages of around 1.54 volts, you'll still get around 1.5mv resolution.=20 =20 Regards, Jim > -------- Original Message -------- > Subject: Re: [EE] Accurate measurement of battery voltage > From: V G > Date: Mon, November 22, 2010 12:00 pm > To: "Microcontroller discussion list - Public." >=20 >=20 > Hi all, thanks for the replies. >=20 > The purpose is to make a battery charger/discharger/cycler/profiler. I > want to be able to accurately detect end of charge and "almost dead" > states using delta V. Plotting discharge curves would also show true > battery capacity. >=20 > I ordered some Maxim samples of 14 bit ADCs, which should give > better-than-millivolt accuracy, but as everyone said, > noise/temperature/other stuff will make that accuracy irrelevant. >=20 > I'll just go ahead and use the 10 bit ADC on the PIC. Also cool since > the PIC has multiple ADC channels. >=20 > I'm going to be measuring NiMH voltages only, so around 0 - 1.5 volts > is an acceptable range per channel. Should give me far better accuracy > than I need. > --=20 > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .