fluctuating voltage/flickering lights (med. rpm)

[BrApple]

observed issue, when engine speed is about about 3k rpm or above my voltage gage will fluctuate rapidly between about 14.1 and 14.7 volts when I have a load on, ie lights, fan, ac or all of the above. when there is no load, nothing is on the voltage sits right at 14.7 volts as it should at any rpm. when there is no load the voltage is 14.7 at idle, but with a load or a heavy load the voltage will drop to 13 or less at idle. when the voltage is rapidly fluctuating I can see it is all of my lights, interior and exterior

I have read the post about the wiring fix and I am not sure that that applies here, when first starting the car the voltage goes right to 14.7 volts and does not fluctuate...

I feel there isn't a connection problem as with out a load the alternator is working correctly as noted by my volt gage and reading across the battery ...

battery is a brand new Optima redtop, new Autolite alternator and Nima's lightened and underdriven pulleys

so the low voltage at idle under load may be because of the pulleys as as soon as you rev the car up the voltage jumps to 14.7 and the lights get brighter ...

if I can do it the plan is to get home this afternoon and verify that the connections are good, and maybe switch back to the stock pulley for the alternator ...

any other thoughts?

could it really be the wiring?

this problem just started after the new alternator, previous alternator was not charging fully, in the morning it would put out 14.7 volts, but as the day went on it would drop off some, and from time to time it would drop to about 13.5 and stay there, but one brush was very worn and might have stopped making contact all of the time leaving just one brush working ...

 

[GoldnTour]

The wiring fix is intended for flickering and dimming. when i was going thorough witht this issue, the voltage was always good around 14~, the fluctuations might be caused by current fluctuations. this mightn not make sense because I=V/R and since load and voltage stay the same it I should not change. the wiring fix is for the ref voltage of the alternator, since the alt puts out an ac signal yopu cannot measure the current output unless you break the circuit. if you cant find loose grounds, just do the wiring fix, its free and it will only take an hour or two.
oh yeah and i had a new alt and new optima red top.

 

[BrApple]

well, I went to put the stock pulley back on and the battery light came on ... got the alternator tested and it is good, finally found that a fuse went turning the battery light on ...

ended up putting the old alternator back into the car ... no flicking lights, but the voltage did drop off under load as before


will try the new alternator again tomorrow to determine if it still causes a vlotage fluctuation and flickering lights with the stock pulley which I hope it does because that means it is the alternator not the pullies

 

[Tony2005]

The wiring fix is intended for flickering and dimming. when i was going thorough witht this issue, the voltage was always good around 14~, the fluctuations might be caused by current fluctuations. this mightn not make sense because I=V/R and since load and voltage stay the same it I should not change. the wiring fix is for the ref voltage of the alternator, since the alt puts out an ac signal yopu cannot measure the current output unless you break the circuit. if you cant find loose grounds, just do the wiring fix, its free and it will only take an hour or two.
oh yeah and i had a new alt and new optima red top.

Actually, Crystian, it makes perfect sense. V=IR. If the voltage is constant (as in alternator is working fine and the voltage regulator is working fine), and the resistance is changing (due to a bad or loose reference voltage wire), then the current will change regularly causing the flickering Battery/Charge light.

 

[GoldnTour]

Actually, Crystian, it makes perfect sense. V=IR. If the voltage is constant (as in alternator is working fine and the voltage regulator is working fine), and the resistance is changing (due to a bad or loose reference voltage wire), then the current will change regularly causing the flickering Battery/Charge light.

my meter is not quick enough to measure the diff, i wish i had an oscope

 

[BrApple]

not sure if I stated this or not before but to put some closer on this particular thread, the flickering on my headlights at rpm was the alternator itself, I swapped my old one back in and the lights didn't flicker ... so much for buying a new alternator ...


on another note, with just lights on my "old" alternator is now staying at about 14.2 volts on my gage all the time, but it will drop more when I crank the AC with the lights on ...