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Discussion Starter · #1 ·
My battery is 12 volts with engine off. When started, I am only getting 11 volts, at idle or above. Is my alternator not doing it's job? Its 105 amp, one wire, and Only electronics im running are stereo, electric fans, and lights, Msd box, ect. Nothing rediculous. Could that make my electric fans not run at their full potential? Thanks
 

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My battery is 12 volts with engine off. When started, I am only getting 11 volts, at idle or above. Is my alternator not doing it's job? Its 105 amp, one wire, and Only electronics im running are stereo, electric fans, and lights, Msd box, ect. Nothing rediculous. Could that make my electric fans not run at their full potential? Thanks
It aint workin... Is it faster with the stereo on?
 

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It doesnt sound like your alternator is working. I would remove it and have it independantly tested. Did it sit for a long period of time recently. By long period I mean over 3 months.
 

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My battery is 12 volts with engine off. When started, I am only getting 11 volts, at idle or above. Is my alternator not doing it's job? Its 105 amp, one wire, and Only electronics im running are stereo, electric fans, and lights, Msd box, ect. Nothing rediculous. Could that make my electric fans not run at their full potential? Thanks
Do you have a large diameter pulley on it ? That will slow it down.
 

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Discussion Starter · #6 ·
Ive got the stock size pulley on it. I'll pull it off and see if it tests good. Its sat for prob. 4-5 months. Almost new though, less than a year old. Could it be in the wiring as well?
 

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Well it could be your rotor has lost its magnetism. So try this before taking it off:

I am asuming it is a GM unit. It will have either two prongs on the side where the regulator is, or a rectangular plug with four prongs in it. You have only the main battery cable connected to the alternaotr, no other wires correct? If you have a wire going to your regulator, disregard the rest of this and just take it off and have it tested.

The motor must be running to do this, so be very careful. Hook a test light to the positive of the battery (or the main post at the back of the battery) and then first check that it lights up if you touch the alternator case. If it doesnt then you have either a ground issue or the light isnt hook to a battery.
If it lights up, then touch the probe end of the test light to the prongs in the regulator (touch them all it doesnt matter). If you hear the engine kick down a bit, I would suspect your alternator just turned on. But check it with a volt meter anyway.
If it stays the same, then I would remove it for testing.

If it is turned on and everything looks ok. I would then shut it off, and let it sit for about 1 minute. Then start it back up. If it is not charging again, remove it. Take it to a local rebuilder and have him install a new rotor in it. What has happened is the vibration from your motor has shaken the pole pieces on the rotor loose so that they will not hold their magnetism. (Which is what a one wire alternator uses to turn on)
 

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Discussion Starter · #8 ·
okay, so it kicks on but still only reads 12 volts. So what Im getting out of this is the rotor is bad?
 
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