Alternator Voltage Reading

[])R@G()N]

yeah I have one,

with out anything running its 12.7volts which why I think its not the battery, would be good if it was would save me a few hundred on a new alternator.

whats happening is when the cars running and I have the high beam headlights and blower fan going the Voltage slowly drops down to 12v within under a minute.
When its reving 2500rpm+ it will come up to 13.9 I don't think its doing this all the time though becasue the other day I was driving around for over 1 1\2 hour and stopped for a few minutes at the young blokes house and went to start it again and it was dead it would only turn the motor over once.

 

[don0xer]

with a brand new alternator + battery i had 14.3v at alternator, 14.2v at battery and 13.6v on the cluster. over time i had a few dramas so i changed the reg over after 3 yrs of use. now its 14.4v at alternator, 14.3 at battery, and 13.9-14.0v at cluster.

all at idle, no ac or lights on.

today as is, 3yr old batt/alternator + new reg about 12.9v car with ignition off

 

[IBLOWN]

It will flicker if its fluctuating between numbers. The volt reading in the cluster is very sensitive but really should only be flickering after the decimal point unless its flickering between 12.9 and 13.0 or something. That would explain why you cant read any of the numbers.

 

[])R@G()N]

I took it for a 10min drive and it just stayed the same (flickering)
well acutely it doesn't have a dot . at all now that your have mentioned it, Shouldn't there be 3 numbers displaying ?

 

[Cúl-Báire]

A little OT, what is your idle speed?.. It shouldn't be dropping below 12.5v at idle with your AUX gear running. This makes me think the idle speed is maybe a little on the low side, and not giving the alternator enough RPM to charge properly while idling (an alternator will only charge to a certain capacity between an RPM range).

 

[accentstencil]

Shouldn't there be 3 numbers displaying ?

Yes, three digits with a dot between the second and third, assuming that the voltage is 10 or above, lower than that it would be 2 digits.

 

[])R@G()N]

Well today I went and got the battery tested and they reckon it was stuffed, So I got a brand new one and its still charging the same,
I just had the multi-meter on it with A\C and the lights On the volts are dropping to 12.0- 11.9v after a few minutes.

 

[wrx884]

who told u ur battery was stuffed? if u were gettin a reading of 12.7v on just the battery thats wat a new battery should b reading neways.

Ur regulator on the alt needs changing as its on its way out.

 

[])R@G()N]

Some battery joint tested it, I think it was called redpoint
I changed the regulator when It first started playingup.

After having a think about it, I took the battery back and got my money back and when and brought a brand new Alternator.
Tomorrow I'll fit it and with fingers crossed the end of these problems.

 

[])R@G()N]

Ok I couldn't wait so I when and put the New Alternator on.

New readings
@ Idle 14.5volts
Under load A\C flat out and High Beam on drops to 12.5v on Idle after a few mins,

Hopefully this is the end of this problem

I also found out what was going on with the voltage display on the cluster :embarrass
I was holding the "DOWN" button and the "MODE" button instead of the "UP" botton "MODE" button :doh:

ThanX All for the help :beer chug:

Rep points for you all :thumbsup: