Normal Battery Voltages:
With your Jeep off most wet batteries will read 12.5-12.8 volts with a full charge. Many gel filled batteries (Ex: Optima) can be closer to 12.2-12.5 at full charge. While cranking over the motor, your battery should never drop below 10.5 volts, if it does, either your battery or your starter is bad. With the Jeep running, your voltage should be between 14-14.9 volts. 13.0-15.0 volts is acceptable, but it should be 14 something.
Related Writeups: | Multi-Meter Basics |