Alternator Output
06-05-2008, 01:54 PM
#1
Racer
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Alternator Output
I have a 1984 Carrera with a stock 3.2 
Can you tell me what the output voltage from the alternator should be at idle under no load and also under load.
What is too high of voltage?
Thank you.
Can you tell me what the output voltage from the alternator should be at idle under no load and also under load.
What is too high of voltage?
Thank you.
06-05-2008, 02:38 PM
#2
Addict
Quote from bentely: a reading much higher than 14.2 volts most likely indicates a faulty voltage regulator. a reading below 13.5 volts volts means that the battery is not adequately charged. this may be due to: faulty V-belt, faulty voltage regulator, faulty voltage regulator.
06-05-2008, 04:06 PM
#4
Team Owner
mine is 13.2 and my car is working just fine. I just got this reading last night. a i was doing my Co checks, the analyser reported it. . This was at an idle of 950
06-06-2008, 07:46 AM
#5
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greetings
the alternator isn't really performing at dead idle.
if you kick it up to at least 1,500 rpm, after running the car long enough to recharge start up drain, the voltage becomes a bit dependent on battery age. A very good battery should allow the V to be around 13.8 or 13.9 without any loads. A relatively "worn" battery might allow 14.1. At 14.1 the battery load test may read 50-60%.
If you turn on the high beams and blower motors the V drop from your baseline may be around .1 or .2 when you have the idle high.
Different alt mfg may show slight differences. Valeos are pretty consistant.
Also... the most needed additional gauge in our 911s is a voltage gauge. It doesn't have to be driving line of sight like an oil temp gauge. Hanging under dash or in the console is good enough. Besides hot rod suppliers there is also small aircraft gauges like those pushed in the Aircraft Spruce cat. Of course there are also VDOs around.
The issue is beyond voltage drop. A failed regulator may allow your alternator to push out enough voltage to fry your ignition system and headlights..
i'm no pro
the alternator isn't really performing at dead idle.
if you kick it up to at least 1,500 rpm, after running the car long enough to recharge start up drain, the voltage becomes a bit dependent on battery age. A very good battery should allow the V to be around 13.8 or 13.9 without any loads. A relatively "worn" battery might allow 14.1. At 14.1 the battery load test may read 50-60%.
If you turn on the high beams and blower motors the V drop from your baseline may be around .1 or .2 when you have the idle high.
Different alt mfg may show slight differences. Valeos are pretty consistant.
Also... the most needed additional gauge in our 911s is a voltage gauge. It doesn't have to be driving line of sight like an oil temp gauge. Hanging under dash or in the console is good enough. Besides hot rod suppliers there is also small aircraft gauges like those pushed in the Aircraft Spruce cat. Of course there are also VDOs around.
The issue is beyond voltage drop. A failed regulator may allow your alternator to push out enough voltage to fry your ignition system and headlights..
i'm no pro
06-06-2008, 07:54 AM
#7
Team Owner
.it is actually one of my most glanced at guages ...between that, my keen nose for sulpher, and my back up alternator in the garage .. figure i am good to go ...
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06-06-2008, 08:10 AM
#8
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exactly......
I love colors on gauges. Makes for faster glancing.
ps: i just noticed my signature is gone and they have me listed as a member. WTF I paid for life, I think?
I love colors on gauges. Makes for faster glancing.
ps: i just noticed my signature is gone and they have me listed as a member. WTF I paid for life, I think?
Last edited by RoninLB; 06-06-2008 at 08:12 AM. Reason: wow
06-06-2008, 04:52 PM
#10
Burning Brakes
Call to AAA...
sorry, couldn't help myself...I am in a good mood today
abe
06-06-2008, 06:37 PM
#11
Team Owner
well ya know ..... i have a story about that ... hahahahah
PS went basting by the CN tower, SKydome and Air Canada Center the other night on the gardener with the high cement walls, what a roar that engine makes at high RPM .. Holy crappers Batman
PS went basting by the CN tower, SKydome and Air Canada Center the other night on the gardener with the high cement walls, what a roar that engine makes at high RPM .. Holy crappers Batman
