I've been working on trying to design a circuit which will allow me to 
monitor state-of-charge and charge/discharge current for solar sites.  
I'd love to use the onboard ADC on a typical PIC to keep the cost down, 
but this isn't necessarily 100% a requirement.

Array voltage is easy.. Just attach to ADC through some precision 
resistors and away you go.   Current not so much, since I will be using 
a shunt to get the current information (unless there's an easier way to 
measure up to tens of amps DC).  The basic configuration would be simply 
to measure the drop across one shunt, although it would be nice to be 
able to do more than one (I.E. one for the charge path and one for the 
discharge path, or perhaps one for solar in and one for wind in and one 
for load out).  

If I require the shunt on the neutral side, I can then measure anything 
positive - but the negative swing is an issue.  If the shunt is on the 
high side, then I have an issue with the high side rail.

How do people typically measure + and - voltages which come off of the 
DCA shunt?

-forrest
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