Voltage regulator ?

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Joined
May 26, 2013
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michigan
My Car
1973 red convertible 351 4 V
What should the correct voltage be? I have between 14.65 and 14.75 volts at the battery with the car running. The light are brighter than normal and have a flicker that's new on the head lights and tail lights.
I have a Motorcraft electronic regulator that about 4 years old.



John J
 
I agree, the voltage is a bit higher than what I would want to see. I like 13.2 - 13.8, but anything under 14.2 is fine bcefore I begin to get excited, although I have seen some specs say up to 14.5 is okay. I rarely see much over 14.2 on the First Generation Mustangs. The voltage you re seeing is not horrendously high, but there is no sense in risking perpetually overcharging the battery or sending more voltage than needed through the lamp filaments. A shop teacher of mine once said it a bulb needs to be replaced always check the voltage from the charging system in case the filament failed due to excess voltage. Although I never ran into a problem with charging voltage when I replaced bulbs, I felt it was a good habit to get into.

Before replacing anything it may be a good idea to check the voltage with one or two other voltmeters, just to make certain yours is reading about the same as the others. I rarely see the digital voltmeters give problems, but the older analog meters could cause grief after a few years of use.
 
Thanks for the info everyone. I thought it was too high. The lights are little to bright for me. I don't want to have to replace them anytime time soon. I checked the voltage with my fluke digital meter again today with the same voltage reading. I am going to pick up a new one from NPD in Charlotte.



John J
 
Hi,

Sorry for opening old topic instead of creating new one but I feel like my question fits here.

What should be charging voltage on a battery on idle and while driving?
Should it be the same all the time or it may drastically change?

For me, on idle, I see like 12.2V (with lights on) or 12.8 (lights off); while driving i can see like 13.5-14.5V depends on the speed...

I don't think it's how it should be but I would like to confirm.

The alternator has been renewed and regulator replaced to new one (electronic).

Cheers.
 
Hi,

Sorry for opening old topic instead of creating new one but I feel like my question fits here.

What should be charging voltage on a battery on idle and while driving?
Should it be the same all the time or it may drastically change?

For me, on idle, I see like 12.2V (with lights on) or 12.8 (lights off); while driving i can see like 13.5-14.5V depends on the speed...

I don't think it's how it should be but I would like to confirm.

The alternator has been renewed and regulator replaced to new one (electronic).

Cheers.
I have underdrive pulleys on one of my cars. I happened to check the voltage yesterday. 12.4v idling around 800rpm without the lights on. It's been going strong like that for years. Even does fine with dual electric fans.

If anything, maybe the battery doesn't charge as fast or the headlights aren't as bright as if the voltage was up around 13.4.


On another car with factory pulleys and ford alternator, it hangs out at 13.4v while idling around 800rpm.
 
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