Soo - in a project I'm working on there will be 3 li-poly batteries in series. This means at full charge they'll be at ~14.6V. What is the best way to monitor this voltage from an AVR's ADC? The only idea that I have is to put a very high resistance resistor divider across them, but I don't really like that for a variety of reasons (constant load (though small) on batteries as well as figuring out how input impedance of ADC input affects resistor divider, among other things). I suppose I could monitor the voltage of just one battery - but I don't really think that is a good solution either.
Soo - any suggestions?