Where did my voltage go?

[jim0207]

Cold start up I had 14.3 volts. Drove a few miles I noticed my voltage was down to 11.9. The voltage moved between 11.3 to 11.9 as I drove 55 mph. At idle or 1900 rpm's voltage stayed low. New battery, good wires, clean and tight terminals. I replaced the alternator ? years ago. By the way I turned on my hi beams to see if the voltage would change. It did. It went up to 13.4voltage. It stayed there all the way home. Just a few miles away from were I had noticed the voltage had dropped. So, were did my voltage go?

 

[Nick Micale]

...................... So, were did my voltage go?

The best way to find out is take it in to a auto parts store like Autozone and have it checked for free.

My street car kills an alt about once a year which is why i purchase them with a life time warranty. These alts do not hold up well, especially at high RPM like 6000 or so, never had one last 7 years!

The one I replaced last week had a smaller pulley than stock, so the alt is spinning way too fast in my application. I changed to a stock pulley on the new one.

 

[jim0207]

The best way to find out is take it in to a auto parts store like Autozone and have it checked for free.

My street car kills an alt about once a year which is why i purchase them with a life time warranty. These alts do not hold up well, especially at high RPM like 6000 or so, never had one last 7 years!

The one I replaced last week had a smaller pulley than stock, so the alt is spinning way too fast in my application. I changed to a stock pulley on the new one.

Thanks, good point about the life time warranties at AZ. I did have the small alt pulley for a lot of miles and hi rpm's. It's been replaced by the original pulley. On the voltage lose. Exciter could be going bad, maybe.

Cold start up I had 14.3 volts. Drove a few miles I noticed my voltage was down to 11.9. The voltage moved between 11.3 to 11.9 as I drove 55 mph. At idle or 1900 rpm's voltage stayed low. New battery, good wires, clean and tight terminals. I replaced the alternator ? years ago. By the way I turned on my hi beams to see if the voltage would change. It did. It went up to 13.4voltage. It stayed there all the way home. Just a few miles away from were I had noticed the voltage had dropped. So, were did my voltage go?