Car turns off 2 minutes after a jump start... what could this be?

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Oct 26, 2011 | 11:31 PM
  #1  
Here's the short and sweet version so you all have an idea of what I'm dealing with right now.

I went to start up my car like usual this evening, and it didn't start up. I opened the door, all the lights were fine (flood lights, head lights) but there was absolutely NO CRANK. Headlights are now very very dim, courtesy light is dim, air bag light is dim.

OK. I get a jump start. Everything is good. I drive around for about an hour and end up needing to get some gas. So I do. Car is still on while Im pumping. Get done pumping, get in the car, and a few seconds later, engine stops, all the lights are very faint. Multimeter reads 5VDC on the battery... so I get a jump start, again.

Car cranks right up, takes less than a second. One minute later, engine halts to a stop again. Between the jump start and the car halting, the voltage was a constant 13vdc. So the alternator is fine i am assuming. Is this my battery acting up, or something weird like my ECU? Anyone experience this crap before?
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Oct 26, 2011 | 11:36 PM
  #2  
Check the charge output from the alternator just to make sure, doesn't hurt to check
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Oct 27, 2011 | 02:42 AM
  #3  
Alternator bro. Battery seems to be fine but the alternator isnt charging it hence the dim lights and the car not staying on for long.
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Oct 27, 2011 | 04:41 AM
  #4  
Yup, the alternator is dead.
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Oct 27, 2011 | 06:42 AM
  #5  
If you saw 13V then may be it is the battery which has shorted cell insides. Battery is the cheapest of the component. If you saw 5V at the battery, then it is goner already. Get a new battery and then you will know if you also need new alternator. You should have the battery+brake light on if your alternator was not charging. Since you did not mention it, I am assuming you did not have those two red light on after the car was started.

If there is *any* problem with the electrical system in *any* car, first thing to replace (if you are so inclined) is the battery. Just assume it is dead if it is over one year old. It only costs $50 to $100 which is cheaper than anybody else looking at your car. While replacing the battery, you should also fix all the cable corrosion. There are had been quite a few incidents where I spent inordinate amount of efforts only to realize that battery had gone bad prematurely. When it develops internal short, it really wrecks havoc with the rest of electrical system.

- Vikas
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Oct 27, 2011 | 07:32 AM
  #6  
yeah sounds like low water in the battery, if it's a serviceable type (has caps you can pop off), then fill it with distilled water, charge it, and try again. If the issue persists, then I would replace the battery.

I wouldn't be so quick to replace the alternator just yet, even though it does sound like it may be a main contributor to the issues. There are other things you need to check first.
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