Loose Alt. Belt = Battery Not charging?

Posted by blMuskrat, Apr 29, 2004
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  1. blMuskrat

    blMuskrat Proven Member

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    Ok, Roughly 6 months ago I sent the alternator out to be rebuilt. when they put it back in, the belts were a little lose. Now, the belt have about 1/2" to 1" give, I was wondering if this could cause the battery to not charge AT ALL, or if it's the alt again.
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  2. boostineklipz

    boostineklipz Proven Member

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    The battery should not lose charge. All the battery does is start the car and give electricty to the car when the altenator is not running. A lose altenator belt would not have much effect on the battery. My guess is if the car is having problems starting, its the battery but if the car is having trouble staying on after the car has been started then my guess it would be the altenator.

    If the battery is losing charge its probably a bad altenator because the altenator cannot put enough volts out to keep up with the car so it resources itself to the battery which will cause the battery to lose charge.

    Hope that helps some.

    Easy way to tell if its the altenator or the battery... Start the car, remove the battery while the car is running and see if the car dies. If it dies than it is the altenator.
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  3. blMuskrat

    blMuskrat Proven Member

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    Thanks, I think that answered part of it. But if the belt was lose enough, could it cause it to not produce enough power to run the car and charge the battery?
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  4. Slappster

    Slappster Proven Member

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    That belt shouldnt have much play at all. Tighten that sucker, if that doesnt help check the alt fuse then if its not that get a new battery.
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  5. Jdmturbo

    Jdmturbo Awaiting Email Verification

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    I have the same problem, except belt is tight, this is second new alt.(argued w/ guy @ Autozone to get new one since old one tested fine) Alt. fuse is fine,have new battery from Autozone and a Optima(for future) ran new 4gauge cable from B+ on Alt. to Alt. fuse and still when I start the car(reads 14.4 volts) and it runs with a digital voltmeter on the battery the voltage drops .10 every 10-30seconds and eventually the battery dies.(?)

    I have a couple more tests to do, but good luck on your situation.
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  6. blMuskrat

    blMuskrat Proven Member

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    Do you have a system in your car? It sounds like you have a drain on the battery and the alt doesn't put out enough amps to compensate. The 14.4 reading is normal for a charging battery. Just my guess.
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  7. blMuskrat

    blMuskrat Proven Member

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    Update: The loss of power was due to a loose alt. belt.

    My Hypothesis: The belt was loose tobegin with, and sometime, about a week ago, the alt. belt skipped a rail, causing it to rub against someone(and change the pitch of the squeal :) ), and causeing it to loosen more.
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  8. tavas

    tavas Probationary Member

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    To JDMturbo
    You say you changed the positive cable, did you change the negative as well. Electricty needs the complete circuit to be in good condition so you may have a bad cable on the negative side.

    Also check the amps the alt is putting out. Generally a standard alt will put out around 55 amps. This works fine for normal operating but if you have a big stereo system, they can put too much of a load on the battery and the alt won't keep up. Hence the battery won't get the charge into it even though the voltage is fine. Eventually it will go flat. Usually if the stereo is powerful, it's wise to install a bigger alt (around 80 amps) and maybe some capacitors. Get an auto sparky to check the amps out. Car stereo installers can help with stereo setup. That bit is beyond me.

    hope that helps.
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