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HO Alternator putting out low voltage?

Printed From: the12volt.com
Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=54728
Printed Date: May 14, 2025 at 7:36 AM


Topic: HO Alternator putting out low voltage?

Posted By: scarmitri
Subject: HO Alternator putting out low voltage?
Date Posted: April 27, 2005 at 1:41 PM

I recently purchased a HO alternator. When i did voltage test it reads 13.0-13.6v at idle with nothing on (stereo, fan, lights, are all off). With everything on it drops to 12.5-12.9v. My alternator is as follows from the test results given to me from where i got it. 

Maximum output                       [A]: 172                           Stator Voltage                           [V]: 5.8

Regulator set point                  [V]: 14.8                          Secondary Regulation            [V]: 14.8

Turn on speed                    [RPM]:1415

Output @ 2000RPM                [A]: 65

Output @ 5000RPM                [A]:162

With everything off when i come to a light my headlights dim. My stock alternator did not do that. All those numbers are at alternator rpm and i was told even at engine idle i will have more output than stock. My question is  the voltage regulator not working properly? When engine is reved the voltage is 13.6-14.2 with no accesories on. If they are it drops will drop with them on.

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1996 Chevy monte carlo LS

2 -12" phoenix gold octane zr

1-rockford fosgate class d 1001bd 1000w rms @ 2 ohm max 2000w

1- 1farad pheonix gold cap




Replies:

Posted By: Francious70
Date Posted: April 27, 2005 at 3:22 PM
Try a little somthing for me. Check and see if the "Bass Boost" is turned up on your amp. If it is, turn it down until the headlight dimming stops.

Somthing else you could try is to put a smaller pully on the alternator to increase the RPMs of it at idle.

And 12 volts at idle from you alternator is just a squeek to low. You might wanna see if the regulator is bad.

Paul




Posted By: scarmitri
Date Posted: April 27, 2005 at 3:40 PM
Its just when i come to the light my headlight go dim even without the stereo turned on. a have an external bass boost control and its turned down i have no problem when im driving. Its the voltage that im worried about.




Posted By: Master Asylum
Date Posted: April 27, 2005 at 4:11 PM
You might wanna ask the people that provided you with the alternator. I personally found that part of my vehicle a bitch to deal with and I went through a bad company. (Alterstart still sucks.) Got a 98 Chevy MC LS. Apparently at idle these vehicles suck.

-------------
1998 Monte Carlo w/
Eclipse CD8454
2xRockford 5.25" Power 2-way T152C
2xRockford 6"x9" Punch 3-way FRC4369
1xMemphis 16-MCH1300 5-channel
2xKicker 12" L5 Solobaric-2 Ohm




Posted By: Francious70
Date Posted: April 27, 2005 at 5:00 PM
My GF drives a '97 MC. It seems to do pretty well at idle, but then again, everything is stock.

Paul




Posted By: scarmitri
Date Posted: April 27, 2005 at 10:14 PM

i went there and they ran test as well. Told me to change belt tensioner and belt but still no difference. The shop is about 1 hour away from me, i guess i have to go pay them another visit.





Posted By: BIGho
Date Posted: May 19, 2005 at 12:57 AM
Where did you buy your high output alt from. There are some real bad suppliers out there?





Posted By: supradude
Date Posted: May 19, 2005 at 7:00 PM
Yes, if its from alterstart and like the one they sold me it will never work. There are good suppliers out there though (wish I had knew this before I wasted my money).

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'85 Toy





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