I have been in the industry for many years and enjoy your magazine very much. In the Tech Feature, Zapping Warranty Returns (January, 2007), Larry Carley writes that, at idle, most charging systems, with no load, produce 13.8 to 15.3 volts. What happened to the old-school 14.3 volts? When did this new voltage come about?
Larry Carley responds:
Mike, the charging system voltage varies with the ambient temperature, which is why I gave a range of possible charging voltages. A charging voltage of 14.3 volts is still a good average for most vehicles, but it can vary. So don't think an alternator is bad if the voltage is slightly higher or lower than 14.3 volts.