Measure the battery voltage with an inexpensive digital voltmeter with the engine off. It should read near 12.6 volts when it's fully charged. If it's around 12.0 volts, it's good but discharged. At 11.0 volts, suspect a shorted cell.
With the engine running, it must measure between 13.75 and 14.75 volts. If it stays around 12 volts, there are tests to determine if the generator, voltage regulator, or wiring are the problem.
Sunday, November 28th, 2010 AT 5:27 AM