alternator
05-18-2005, 03:14 PM
#1
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ok so my volt meter was reading 18+ volts so i checked it out one day after work, sure enuf 16.8 at idle and 18.9 at half/full throttle...so i got a new alternator under warenty because this one is a month mabey 2 old....so the new one works fine(only ran it for 5-10 mins), so i hook up my second battery, everything working fine, then my car starts acting up like it did before and sure enuf, the gauge reads over 18 volts again....so know im getting mad....so does anyone out there know why this is happening...i have an optima red top under the hood and a yellow top in the back....running 1/0 awg wire thru the car and 2 8awg from alt to batt...its just an oem 78 amp alt...could it just be i need a bigger alt, or is soemthing else wrong...thnx in advance
05-18-2005, 03:55 PM
#3
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How are you hooking up the second battery? It seems to me that if everything is working fine till you hook up the second battery, the second battery may have something to do with the problem. Otherwise where is your voltage regulator, is it built into the alternator?
05-18-2005, 07:47 PM
#4
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i have the positive to positive and neg to neg of the batts, the alternator worked just fine for like 20-30 mins with both batts hooked up, i let it sit and run for a while with both hooked up, then i drive away and the cars volt meter jumped to 18+ volts, i thought it was my gauge being messed since its stock from 84, but i hooked it up to a good volt meter up at the shop yesterday and it infact was over 18 volts, even the scanner for the computer read over 18 volts....i have no clue where the meters hooked up, im assuming thru the alternator, cuz theres 2 wires in a clip that plug into it and then one runs to the power...i was just wondering if there was an actual reason for this or should i just get the bigger alt i was looking into?...this is also the second yellowtop i have gone thru, the last one was hissing(from overcharge, 18 volts will do that), so i brought it back and got another one, the batt was fine till it read over 18 then it hissed a bit so i unhooked it, still reads over 18 tho.....any other thoughts?...thnx for the responses
oh and the regulator, is probably just built into it, its a stock alternator
[ May 18, 2005, 08:49 PM: Message edited by: Mat-Romain ]
oh and the regulator, is probably just built into it, its a stock alternator
[ May 18, 2005, 08:49 PM: Message edited by: Mat-Romain ]
05-18-2005, 11:13 PM
#5
500 Watt CAFz'r
Join Date: Apr 2004
Posts: 756
First, clean and tighten all battery terminals. Corrosion & loose terminals can do many weird things.
K I dunno what your car is, so:
If it's GM, yes, the regulator is built-in. Pull the alternator off and take it to an alternator shop and get them to bench test it, noting output voltage. If it's an old car, check that the regulator plug on the alternator has clean, tight connections.
If it's a Chrysler product, the regulator may be an integral part of the ECM computer. Although rare for it to go, with extreme audio anything can happen. Get the car tested at a shop.
One of your Optimas could be kaput. Alternators do weird things when an Optima blows. I have a car audio shop's demo car at my shop right now as it has blown two custom alternators and they're not sure why. Most likely one of the FIVE Optimas in it has gone south. I'll know more tomorrow after I go over it.
Also, alternators are NOT battery chargers. ALWAYS charger your battery(s) with external equipment when replacing alternators.
K I dunno what your car is, so:
If it's GM, yes, the regulator is built-in. Pull the alternator off and take it to an alternator shop and get them to bench test it, noting output voltage. If it's an old car, check that the regulator plug on the alternator has clean, tight connections.
If it's a Chrysler product, the regulator may be an integral part of the ECM computer. Although rare for it to go, with extreme audio anything can happen. Get the car tested at a shop.
One of your Optimas could be kaput. Alternators do weird things when an Optima blows. I have a car audio shop's demo car at my shop right now as it has blown two custom alternators and they're not sure why. Most likely one of the FIVE Optimas in it has gone south. I'll know more tomorrow after I go over it.
Also, alternators are NOT battery chargers. ALWAYS charger your battery(s) with external equipment when replacing alternators.
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