car runs 14.5V when it starts???

AJ/FormS said

I have seen many modern cars running up to 15.5 volts CONTINUOUS charge. Most GMs I have tested are running more than 14.5 volts.

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But let's keep in mind that this is the design voltage set point for these newer systems. 14.5 to 15.5 volts is not the designed setpoint for the older system; it is around 14.0 v. Being off from that number by as much as it is AT LOW IDLE is a problem indicator.

At this point, we don't know what the fast idle/cruise RPM voltage is on this car. And it is hard to know what (quality of) headlights were in the car. So we need some fast idle voltage readings; that will tell the story.

How much AC voltage is OK and how much is not? That should be posted if you are going to do such a test. (Testing for a shorted diode?) There will always some low level of AC in the system. (And I don't know the answer.....)