I will add some of my own research, I have no clue if these will be accurate enough. I will have to talk to an EE:

<h4>Zener Diode</h4>
<p>Use a 10V Zener diode and a resistor in series. Measure the voltage drop across the resistor. Not sure about accuracy. (see www.homepower.com/files/voltmeters.pdf)

<h4>Dual Regulators</h4>
<p>Use 2 10V regulators connected together with the source voltage going to both regs. The AD circuit can measure the difference and higher. (see http://www.e-insite.net/ednmag/archi...2094/02di2.htm)

<h4>Op-Amp Differential</h4>
<p>A 10V voltage regulator can and the battery voltage can be fed into an OP-Amp and one subtracted from the other.
The AD conversion circuit is only required measure 0-5v, which it then adds in the 10v in software.


any more ideas? or thoughts about what is here?

d1