Testing the alternator in car?
#1
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Testing the alternator in car?
So, I recently replaced my battery because the parts store told me it was dead (it's ok since I had a free replacement warranty)...but now it turns out the problem is not my battery.
I can jump-start my car and as long as the battery is hooked-up I can run the car pretty well for as long as I need, until I shut the engine off. Then, I can't restart the car because there's not enough reserve power in the battery.
Someone said that you can test the alternator by disconnecting the negative battery cable while the car's running and if the car dies, then it's most likely the alternator. Well, I did this test and it seemed to be running ok until I applied the brake pedal and the car immediately just died.
It's been suggested to take the alternator to a shop and get them to test it but I don't have any shops around that I trust (especially after the replacement of my other battery). So with that in mind, is there a way to test the voltage coming off of the alternator...and if so, what voltage should it be, etc?
Thanks for any and all help! -Joe
I can jump-start my car and as long as the battery is hooked-up I can run the car pretty well for as long as I need, until I shut the engine off. Then, I can't restart the car because there's not enough reserve power in the battery.
Someone said that you can test the alternator by disconnecting the negative battery cable while the car's running and if the car dies, then it's most likely the alternator. Well, I did this test and it seemed to be running ok until I applied the brake pedal and the car immediately just died.
It's been suggested to take the alternator to a shop and get them to test it but I don't have any shops around that I trust (especially after the replacement of my other battery). So with that in mind, is there a way to test the voltage coming off of the alternator...and if so, what voltage should it be, etc?
Thanks for any and all help! -Joe
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So, I recently replaced my battery because the parts store told me it was dead (it's ok since I had a free replacement warranty)...but now it turns out the problem is not my battery.
I can jump-start my car and as long as the battery is hooked-up I can run the car pretty well for as long as I need, until I shut the engine off. Then, I can't restart the car because there's not enough reserve power in the battery.
Someone said that you can test the alternator by disconnecting the negative battery cable while the car's running and if the car dies, then it's most likely the alternator. Well, I did this test and it seemed to be running ok until I applied the brake pedal and the car immediately just died.
It's been suggested to take the alternator to a shop and get them to test it but I don't have any shops around that I trust (especially after the replacement of my other battery). So with that in mind, is there a way to test the voltage coming off of the alternator...and if so, what voltage should it be, etc?
Thanks for any and all help! -Joe
I can jump-start my car and as long as the battery is hooked-up I can run the car pretty well for as long as I need, until I shut the engine off. Then, I can't restart the car because there's not enough reserve power in the battery.
Someone said that you can test the alternator by disconnecting the negative battery cable while the car's running and if the car dies, then it's most likely the alternator. Well, I did this test and it seemed to be running ok until I applied the brake pedal and the car immediately just died.
It's been suggested to take the alternator to a shop and get them to test it but I don't have any shops around that I trust (especially after the replacement of my other battery). So with that in mind, is there a way to test the voltage coming off of the alternator...and if so, what voltage should it be, etc?
Thanks for any and all help! -Joe
Keeping the battery terminals on ofcourse.
#4
ya you can test battery at AZ... but if you alternator is out wouldn't your car just run off the battery power? and that would usually just last like how much 10-30mins?
#5
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Do you think that you should get the same voltage if you disconnect the battery and then test the cables that "should" be connected? This way you're not also testing the voltage coming off of the battery. Is that thinking correct?
#6
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I'm thinking maybe a poor, or no connection from the alt to the batt. That would would explain why the car is ok after starting. Maybe the battery is not getting any charge and the cranking killed the new battery.
#7
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The easiest way is to just see how much voltage you have at the battery with the car running. If you see around 12V, the alternator is not charging the battery, if you see between 13.6 14.2V then you are getting a charge from the alt.
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