Voltage monitor for car battery

[chuck]

use an op-amp set up has a devider you can then put upto 20v in and get 0-5v out and for safety tie a 5V zener diode to prevent damage to the pic or just a resistor devider

I personal use op-amp has i can measure up to 60V

[peterdeco1]

Hello. I've been using the attached circuit and the following code to measure the battery condition on a 12V sealed rechargable gell cell. The code goes like this:
batterycondition var byte

adcin 1, batterycondition
if batterycondition < 192 then beep

Perhaps tweaking the adcin value would work for lead acid. It may have a different discharge curve.

[passion1]

use an op-amp set up has a devider you can then put upto 20v in and get 0-5v out and for safety tie a 5V zener diode to prevent damage to the pic or just a resistor devider

I personal use op-amp has i can measure up to 60V

Chuck / Jerry

Thanks for the advice! Could you be specific with regard to where the 5V zenere diode must be placed. (I'm rather new to electronics!)

THANKS!