I need to monitor a battery voltage to control charge rate. I have set up the usual volt divider on the 12v battery I am monitoring and decoupled it with 1uF. The binary result is constantly going up and down by about 5 or 6 even with a regulated source. I have tried smoothing and averaging without any success. Since my interest is in the decimal part of the voltage being measured (the usual 13.80v) am I kidding myself or is it possible to tame whatever it is causing the jitter?? What is it that causes the jitter, say using the 3.3v ref on the duemillanova board ??
Cheers ....... Blakus