alt only charges at idle....

[wesl56 10+ year member]

so i have a 200amp alt from motorcityreman and its about a year and a half old, been working fine till about a month ago... problem is, it only charges at idle now... it voltage reads 14.4 at idle but as soon as i rev it up, the voltage drops to around 12 and my battery light comes on... i figured it might have been the belt but i just put a brand new one on and nothing changed...

also, if it was slipping, wouldnt i be able to see it? with the hood opened, i rev it up and the voltage drops but i can see the alternator pulley spinning faster... halp

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[yunvme666 10+ year member]

yea sounds like its crapping out....

 

[lostdaytomorrow 10+ year member]

It's motorcityreman...

Be lucky you got that long out of it.

 

[wesl56 10+ year member]

so it is possible for an alternator to work completely fine at 1500 rpm but not at all at like 2000 rpm? anyone care to explain how this is possible? just from what i know of how alts work, i cant see how this could happen.... either way im taking it out to get bench tested as soon as i get some time later this week

 

[SPL140.2 5,000+ posts]

regulator is gone. Should be an easy fix.

egg

 

[brokeitagain 10+ year member]

i would say a stuck brush or a brush bouncing off of the slip ring

 

[ultimate157 5,000+ posts]

regulator is gone. Should be an easy fix.
egg

x2. Voltage regulator is gone. Happened to my dad's motorcycle. Replaced the regulator and fixed the issue.

 

[wesl56 10+ year member]

the regulator is that little grey box on the back, correct? would i be able to replace this with a regulator for a stock alt, or would i need a special one since its a HO alt? thanx

 

[SPL140.2 5,000+ posts]

the regulator is that little grey box on the back, correct? would i be able to replace this with a regulator for a stock alt, or would i need a special one since its a HO alt? thanx

yes normally it looks like a box and yes you can exchange it out for a stock regulator

egg

 

[wesl56 10+ year member]

any more input before i try this?

 

[Shyne151 10+ year member]

any more input before i try this?

Yah, take the alternator off the car and take it to a alternator shop to get fixed.

 

[audioarsonal 10+ year member]

See if you can get it externally regulated.Then you can run higher voltages if you fell the need.

 

[SPL140.2 5,000+ posts]

See if you can get it externally regulated.Then you can run higher voltages if you fell the need.

just stay under 15 volts or your cars cpu light will go on.

egg

 

[audioarsonal 10+ year member]

just stay under 15 volts or your cars cpu light will go on.
egg

x2 on the 15v.Just a thought for the future.You could always run a step down.But for daily it might not be so pratical since you would need a 16v bank.