batter light at high RPMs

[Dave0803]

I have an 03 GT. When my RPMs get up around 4,000, my votage drops to 12 and my lights dim. I am sure it's the Alt but from what I have seen on here...everyone that as replaced there alt has had to replace them over and over again. Has anyone replaced there alt and not had it break on them again soon after? If so, what kind did they get?

-Dave

 

[85 Coupe 5.0]

Had that problem, was going down the street in 1st at about 4K like a jackass one night, boom, battery light.

from there on, the batt light came on anything above 2K and voltage would drop. Replaced the alt and haven't had problems since.

I would personally test the alt power feeds and such first before I would say it's bad.

 

[Dave0803]

Is there a reason why so many people seem to have this problem happen to them many times after replacing the alt? I didn't think much of it when I saw the light, just thought my alt was going out...no biggie, the car has 86,000 on it. then I saw on here quite a few posts of people with the same problem and when they replaced the alt it would be fixed and develop the same prob soon after.

-Dave

 

[85 Coupe 5.0]

the only explanation I can think of, being a Mustang owner, is that most people here don't cruise around normally. I like to drive mine for what it is, a Mustang. Hence it seems i'm probably a little harder on it than most would be.

Mine sees a lot of high-rpm use. Thinking about that, if the motor is spinning 4K, the alternator is over-driven. if you don't have under drive pullys you're spinning that alt around 15,000 or so, depending. That has to be hard on components, especially the alt's components probably aren't balanced that well to begin with.

My opinion, there probably isn't anything wrong with the people's car's that keep having problems, it's probably just a result of how they are used.