battery help
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Freshman User
Joined: Mar 2006
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From: Sunny Ft Lauderdale
battery help
Hi all. My batteries are dieing. I replaced one about 6 months ago and all was well and then truck wouldn’t start one day. So I replaced the older of the 2 batteries. Truck ran fine for 2 weeks and then wouldn’t start. After reading through the forum I replaced the battery I bought 6 months ago. Now 2 new batteries. Truck ran fine for 2 weeks and then dead again. If I put a charger on the either battery for a night, it will last for about 2 weeks. Any idea? I drive about 400 miles a week. If the alternator was bad, could it run on the batteries that long?
Senior User
Joined: Nov 2002
Posts: 204
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From: Cocoa Beach, FL
That seems like a lon g time to run on batteries. Make sure your belt isn't slipping and test your alternator. If you don't have any way of testing its output just go to Advance Auto or the like, and they will do it for free.
Elder User
Joined: Mar 2006
Posts: 751
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From: Greeneville,TN
I bet it is the alternator. Just go to a parts store to see if they can check your alternator. Many places can check it still on the truck. It takes about 1min to check if it is charging properly.
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Freshman User
Joined: Mar 2006
Posts: 49
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From: Sunny Ft Lauderdale
I pulled the cables off the batteries while running and it died. I am guessing that the alternator is done. Strange as the lights never indicated any troubles. I will do the voltage check and for kicks but it doesnt look good.
Thanks for the tips
Thanks for the tips
Cargo Master
Joined: Jun 2003
Posts: 3,292
Likes: 6
From: Ardenvoir, Washington
Originally Posted by duke_snyder
I pulled the cables off the batteries while running and it died. I am guessing that the alternator is done. Strange as the lights never indicated any troubles.
Thanks for the tips
Thanks for the tips
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Posting Guru
Joined: Feb 2007
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From: Bradenton FL
Im an electrician also have a PSD, i would say the brushes are shot in the alt. or the belt is slipping. Sometimes if you catch it early you can replace the brushes before the alt. goes completely bad but the above advice is your best bet the auto places have mobile testers to see how many amps and volts your alternator is pushing.
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Post Fiend
Joined: Feb 2007
Posts: 14,541
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From: Dallas-Ft. Worth
Originally Posted by duke_snyder
I pulled the cables off the batteries while running and it died. I am guessing that the alternator is done. Strange as the lights never indicated any troubles. I will do the voltage check and for kicks but it doesnt look good.
Thanks for the tips
Thanks for the tips
Has anyone else tried running their trucks on just the alternator? I wouldn't recommend trying it, but if someone has, it would be good info for this problem (and just good to know).
Joe
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Freshman User
Joined: Mar 2006
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From: Sunny Ft Lauderdale
I replaced the alternator and that did it. I would have to say that it must have had just enough life in it to barely run the truck and then it finally died. Thanks for the help.
Fleet Mechanic
Joined: Feb 2007
Posts: 1,852
Likes: 39
Originally Posted by Izzy351
Has anyone else tried running their trucks on just the alternator? I wouldn't recommend trying it, but if someone has, it would be good info for this problem (and just good to know).
Joe
Joe
I wouldn't run without a battery for other reasons. The battery is like a giant filter capacitor, smoothing out all of that ripple from the alternator.
Posting Guru
Joined: Feb 2007
Posts: 1,146
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From: Bradenton FL
It is my understanding of an alternator as working on the principles of a generator of sorts in which converts mechanical energy into electrical energy. Once the engine is running the magnetic field is generated by the spinning of a rotor(magnet) inside a stator(coil of copper). Then producing current from the coil. Some types of motors/generators need an "exciter" current to start and sometimes stay running but im not sure about a truck alternator. Im a journeyman electrician but not an electrical engineer
Fleet Mechanic
Joined: Feb 2007
Posts: 1,852
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Originally Posted by Benny2002
Once the engine is running the magnetic field is generated by the spinning of a rotor(magnet) inside a stator(coil of copper).
Posting Guru
Joined: Feb 2007
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From: Bradenton FL
Getting technical, the alternator produces AC current which then is RECTIFIED into DC which charges the battery, which powers the car and accessories. Removing the battery im assuming breaks the SERIES ciruit and doesnt allow a path back to itself or ground if you will. Then shutting down the car.
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Freshman User
Joined: Mar 2006
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From: Sunny Ft Lauderdale
then why is it on all my other vehicles, when I removed the battery the car still ran? This was how I checked to see if the alternator was bad. Does this only apply to the powerstroke?