http://www.lediouris.net/RaspberryPI/AD ... r-12v.html
I offer this link which might be helpful to some of you.
Here is what I'm trying to do and why that link is helping.
use my RasPi to monitor RV coach batteries (12volt marine batteries) and send me an email if batteries drop below a certain level.
the RasPi will be powered by the 12v batteries in the RV.
If the solar panal on the RV roof doesn't keep the batteries charged above, say 12 volts (which will happen in the summer when I park it under a rain canopy for a week or so between camping trips) then I will get an email if the trailer camper is in my driveway and thus within wifi range, (or if it is at some location where I have signed into the wifi). Actually the scripts and work done by the gentleman at www.lediouris.net
means I'll get a daily email reporting battery level.
I am now buying an ADC, pentiometer, and cobbler to get started.
it might be good to use the RasPi's Bluetooth to send updates directly to my phone as a reminder to check or alert to low battery if we are in a camp ground without wifi.
I am interested in anyone's help or questions. I am just beginning on this and must learn some Java programming to proceed.