# HELP!! Replaced alternator and battery, still no charge!



## kircules (Dec 10, 2007)

1995 nissan sentra XE, automatic with A/C.

About 6 months ago my alternator went. I replaced it and everything worked great. Now six months later, exact same symptoms, battery light, air bag light, radio on and off, then dies. My battery was old so I replaced that and everything ran for three days.

then everything died again. I pulled the alternator and took it to kragen and it failed the test. It had a Lifetime warranty so they replaced it for free.

I put it in and the car ran for 20 minutes then I took it around the block and same stuff, radio, battery lights, then died. 

I checked all my connections, cleaned my terminals and everything checked out fine.

WTF is going on? Am i missing something? 
thanks in advance!
kirk


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## IanH (Feb 11, 2003)

No, chances are the Alternator went bad on you again. The rebuilds are poor quality and if you are unlucky you have to go through a few of them to get a good one.
However I suggest you charge the battery and start the car and check the voltage with the car running, should be about 14.5 - 15 volts.
If its just the battery voltage of 12 - 13 volts then the alternator is not working.


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## kircules (Dec 10, 2007)

I just pulled the old alternator and took it to kragen and it failed. I got another replacement one and had them bench test it three times. It passed all three times. Took it home and installed it. At the terminals i have 11.68 volts. Car didn't start, i jumped it and it went over 13.7v. I checked the terminal on the alternator and it was at 13.7v also. Took off the jumper cables with car running and it died. Terminals down to 11v at both battery and alternator. Checked all the wires i could find, looked around it's all hooked up right. jesus christos, what is going on? this is the 3rd alternator and it passed all the junk at kragen. could my car be damaging these units? I wouldn't think so cause my brand new battery isn't making over 12 GD VOLTS! could my wire harness be garbage? i can't find the problem.

thanks for the advice ian, any other ideas of what i could look around for?


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## sbandara (Dec 12, 2007)

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## IanH (Feb 11, 2003)

well I don't know why it died but 13.7 is good if you have a flat battery.
Was the car you jumped from running ? maybe thats where the13.7 came from.
Check the battery voltage again with everything off and then headlights on to make sure its good. 11.7 is pretty flat, it should be 12v to 13.2 V Max ( a bit higher if just off charge is ok.) and depends a bit on temperature. BTW 10.8 is completely discharged.
So if it starts with a jump we can assume the engine ground is good. 
What could you be doing to damage the alternator.
Not Much !! Alternators automatically current limit, and the (internal) voltage regulator limits the voltage when the battery is fully charged.
Despite what people tell you do not run the alternator with output disconnected, there should be some load for the voltage regulator to work. If not the voltage goes high and will blow up the semiconductors.
Did the Auto shop people disconnect the terminal with the alternator still spinning ?

Well the upshot of this is to charge the battery and try again with the starter. then check the voltage with the car running.
good Luck.


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## SE-R Redline (Dec 12, 2007)

Voltage Regulator???Maybe


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