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Discussion Starter #1
I recently had a problem with my charging system not charging the battery. I replaced the alternator, regulator, battery, ignition switch, and the starter solenoid and corresponding wires, but the battery is still not charging and the generator light won't turn off. It's died on me twice in the same week. Any help would be much appreciated.

Thanks,Elcodude67
 

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How do you know your charging system is not charging??? A dead battery doesn't mean anything, afterall, it could be the battery itself has a bad cell or two in it causing discharge.

When replacing "everything", it only causes more confusion, do one thing at a time to track down the culprit.

What I would do is:

1) take a voltmeter, connect the leads to the actually battery terminals when the engine is running at approx. 1000 rpms. You should read at LEAST 13.8 volts and no more than 14.5 volts for a proper charging system.

If not, are your actual battery wires tight, clean and free of corrosion???

Does your alternator have a good ground?? it needs a firmly tightened bracket to ensure a good ground to the block of the engine.

Then if that doesn't do it,

Replace the voltage regulator.

Then try another alternator.

"NEW" doesn't mean it's good, and just cause a parts places said it "tested good" doesn't always mean much. There simple tests cannot tell if a tiny leakage current is flowing thru a bad diode in the alternator for example.

Joe



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Discussion Starter #3
I got a hold of a voltage tester and connected it to the terminals on the battery and it said the battery was at 13 volts when the engine was off. I started the engine and the voltage went down to about 12 volts. I tested the alternator and it was pumping out 14.2 volts. I am not quite sure what this means, is the regulator bad?

Elcodude67
 

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If the output of the alternator itself was 14.2--how did you get this? Did you get this reading at the battery terminals?, that seems like it is doing it's job. Now try this to make sure your wiring is okay. Take a voltmeter, connect the meter's negative lead to the battery's (+) terminal, and the meter's positive lead to the actual (+) connection on the back of the alternator (terminal with the red wire bolted to it). You should read 0 volts ideally, up to about .5 volts would be acceptable. Any more means there is resistance in the wire from the alternator and the battery. This isn't good as you have a voltage drop.

If that's okay, then yes, suspect the Voltage regulator.

Joe

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Creator of Team Chevelle's RADIO TECH for original audio questions and answers

[This message has been edited by Coppertop (edited 11-02-2000).]

[This message has been edited by Coppertop (edited 11-02-2000).]

[This message has been edited by Coppertop (edited 11-02-2000).]
 

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Discussion Starter #5
I got the 14.2 volts from the alternator, not the battery. The battery was holding 13 volts with the engine off and it dropped to a little over 12 volts with the engine running, which confuses the heck out of me. Now do I need a voltage tester or a resistance tester to test for a voltage drop in the red wire?

I probably don't sound too smart but i've never had any electrical problems this heavy before, and I appreciate the advice.

Elcodude67
 

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Elcodude67


It sounds more and more like your voltage regulator crapped out. The voltage drop I was speaking of is only to double check to see if isn't a charging problem due to bad wiring.

You use a voltmeter set on VOLTs for this test. Just like I said, connect the red lead off of the voltmeter to the Alternator's big power lead where it attaches to the back of the alternator. Connect the meter's black lead to the actual battery (+) terminal.

The idea here is you want ZERO volts. Any voltage would indicate a voltage drop, meaning the wire has resistance--you don't want that! A small voltage like .4 volts would be okay, but certainly not a volt or two! Resistance can come from loose connections or corrosion on terminals or inside the wire itself.

Anyhow, I'd definitely head to the auto store for a new voltage regulator as that reaaaly sounds like the culprit.

Joe
 

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If you have a 2 volt difference from the alternator output stud to the battery, it sounds like the wiring from the alternator to the battery is suspect. Put a temporary wire from the alternator to the battery + terminal and see if the battery voltage comes up to 14. If not you have another problem.Here is another thing to check: with the engine stopped, put your voltmeter on the alternator output stud and see if it has battery voltage. It should. If not, then there is a break in the wire. Also try putting a load on the alternator stud (engine stopped ) by using a lamp bulb connected to the stud and to ground. If the bulb burns dimmer than it does when hooked to the battery, you have high resistance from alternator to battery----dirty connections.
 

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Discussion Starter #8
I checked the resistance in the wire from the alternator to the battery and it read at .2 volts, so I don't think (at least hope not) the wiring is bad. I did notice that when I pulled the ground cable off the battery it sparked. Does this mean that there is a short in the car somewhere drawing power from the battery? I'm still going to try a new regulator and see if that doesn't fix anything.
Elcodude67
 

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Elcodude67,

The .2 volts means your okay. That's very little voltage drop so your wires are okay.

Now, you mentioned about the spark. If the negative terminal sparked when you pulled it off the battery, that means something is drawing current. Perhaps it's a faulty voltage regulator.

However, a lot of things can cause a spark (drawing current) such as a dome light (was the door open when you did this? or aftermarket accessories that have a constant power wire. If everything was completely off, and it's not a voltage regualtor or alternator that's defective, you might have other problems, such as a current draw in the starter for example. Now that I've scared you
, just take it easy and try one thing at a time starting with another voltage regulator.

Joe



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Discussion Starter #10
Thanks for all of the input, you've given a new Chevelle lover hope. Turns out it was the voltage regulator I bought. I bought a $13 Niehoff and new condensor and the thing lights right up and charges at 14 volts. It was almost disaster though because I shorted the battery cable and almost fried the battery. Thanks for the help, I don't know what I would have done without it.

Elcodude67
 
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