At idle you should have over 12 volts. Normally about 13V. When you rev it to around 2000 rpm you should gt at least 13.5V. It should never be less than 12V. Also, check it with the headlights on, and seat heat and/or rear defroster. It should carry a heavy load and still be well above 12V.
Last edited by Flybot; 11-14-2012 at 08:10 AM.