A battery a month!!WTF
Registered User
Joined: Jun 2003
Posts: 180
From: Rochester, NY
If you test the battery with the car off and there is a high amount of draw (more than .2 amps or so) you can test where it is coming from. Using an ampmeter on the battery in series with one of the cables you can pull a fuse and see if the draw was on that current. Once you find which circuit it is on then you have to figure out what thing is causing the draw.. anyways.. good luck
Registered User
Joined: Jan 2004
Posts: 909
From: Martinez,CA
I would say yur alt has a open diode. A diode is an one way electical check valve. It changes the alternating voltage(AC) from the the field windings into direct voltage(DC). If this is the case, the 1 way check valve is now a two way valve. The open diode can drain the battery by allowing voltage to go straight to ground. The only way to test this is to pull the alt apart and test each diode with a doide test. Most multimeters have this function.
Registered User
Joined: Nov 2003
Posts: 195
From: Walla Walla, WA
Originally posted by Robs97Z28
I would say yur alt has a open diode. A diode is an one way electical check valve. It changes the alternating voltage(AC) from the the field windings into direct voltage(DC). If this is the case, the 1 way check valve is now a two way valve. The open diode can drain the battery by allowing voltage to go straight to ground. The only way to test this is to pull the alt apart and test each diode with a doide test. Most multimeters have this function.
I would say yur alt has a open diode. A diode is an one way electical check valve. It changes the alternating voltage(AC) from the the field windings into direct voltage(DC). If this is the case, the 1 way check valve is now a two way valve. The open diode can drain the battery by allowing voltage to go straight to ground. The only way to test this is to pull the alt apart and test each diode with a doide test. Most multimeters have this function.
Thread Starter
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Joined: Aug 2003
Posts: 450
From: Maryland
I am going to swap my alternator and see what happens. It has 120,000 on it anyway. You made a very good point about an open diode. I appreciate everyones suggestions. I'll keep you posted. Oh, do you think I should just go with a stock alt. or is there a better one out there?
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Joined: Sep 2002
Posts: 2,481
From: Arlington, VA
Stock is fine, unless you want to pretty it up with a billet, or maybe a higher output if you have a really powerful stereo system.
But the stocker suffices quite well....I would get it from Jason Chromer for a GM AC Delco OEM one. If you want a cheapy, go get an autozone one. (Thats probably what I'd do
)
But the stocker suffices quite well....I would get it from Jason Chromer for a GM AC Delco OEM one. If you want a cheapy, go get an autozone one. (Thats probably what I'd do
)
Thread Starter
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Joined: Aug 2003
Posts: 450
From: Maryland
Originally posted by scoobysnax83
Stock is fine, unless you want to pretty it up with a billet, or maybe a higher output if you have a really powerful stereo system.
But the stocker suffices quite well....I would get it from Jason Chromer for a GM AC Delco OEM one. If you want a cheapy, go get an autozone one. (Thats probably what I'd do)
Stock is fine, unless you want to pretty it up with a billet, or maybe a higher output if you have a really powerful stereo system.
But the stocker suffices quite well....I would get it from Jason Chromer for a GM AC Delco OEM one. If you want a cheapy, go get an autozone one. (Thats probably what I'd do
)
Thread Starter
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Joined: Aug 2003
Posts: 450
From: Maryland
Re: Re: A battery a month!!WTF
Originally posted by slopokrodrigez
How do you know that?
Remember that the alternator will put out what the battery and electrical system needs up to a point. The current will be different depending on the draw. If the battery is low, the current will be higher and then gets lower as the battery charges.
The easiest way to check the alternator output is with a voltmeter across the battery. When the engine is off you should be measuring about 12.6V. When the engine is running you should measure close to 14V. This shows the alternator is putting out currectly.
I think you have one of 2 problems assuming as you said the alternator is good. Either you have a bad connection and that is creating too high a resistance to properly charge the battery or you have a slow drain when the car is turned off. I'll put my money on a bad connection (assuming as you said the alternator is good). One way to check but don't let it fool you is to measure the battery voltage from the + battery terminal to the frame and then from + to the engine. Both ways should read the same as when you check across the battery.
The first thing to check is the 2 critical grounds at the frame and at the engine. Clean em up and tighten them.
Don't forget the positive cluster on the passenger fender.
With regards to a slow drain, have you installed any electrical components lately? I know those big thumping amps go bad quite a bit and create a draw on the battery when the car is turned off.
You can check for a current draw when the car is off by removing one of the battery cables and putting an ammeter in series with the cable. When the car is off you should not pull much probably like .1 to .2 amps. Remember the radio keeps memory and clock settings so there will be some draw all the time.
Sorry long. I just don't know when to shut up.
I hope I didn't put you to sleep.
How do you know that?
Remember that the alternator will put out what the battery and electrical system needs up to a point. The current will be different depending on the draw. If the battery is low, the current will be higher and then gets lower as the battery charges.
The easiest way to check the alternator output is with a voltmeter across the battery. When the engine is off you should be measuring about 12.6V. When the engine is running you should measure close to 14V. This shows the alternator is putting out currectly.
I think you have one of 2 problems assuming as you said the alternator is good. Either you have a bad connection and that is creating too high a resistance to properly charge the battery or you have a slow drain when the car is turned off. I'll put my money on a bad connection (assuming as you said the alternator is good). One way to check but don't let it fool you is to measure the battery voltage from the + battery terminal to the frame and then from + to the engine. Both ways should read the same as when you check across the battery.
The first thing to check is the 2 critical grounds at the frame and at the engine. Clean em up and tighten them.
Don't forget the positive cluster on the passenger fender.
With regards to a slow drain, have you installed any electrical components lately? I know those big thumping amps go bad quite a bit and create a draw on the battery when the car is turned off.
You can check for a current draw when the car is off by removing one of the battery cables and putting an ammeter in series with the cable. When the car is off you should not pull much probably like .1 to .2 amps. Remember the radio keeps memory and clock settings so there will be some draw all the time.
Sorry long. I just don't know when to shut up.
I hope I didn't put you to sleep.
I checked the alternator output across the battery when the car was off and got 12.3. With the car on it was 14.67. Then I checked for the bad connection from the positive battery terminal to the frame, and then to the engine and got the same reading..12.67. I wasn't quite sure about your instructions on checking for a current draw, so I haven't done that. If that checks out, any other ideas? I appreciate your help.
Thread Starter
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Joined: Aug 2003
Posts: 450
From: Maryland
Originally posted by scoobysnax83
with all the work you are doing, just take the alternator off and to Autozone and take it out of the equation. Then test all the other stuff.
with all the work you are doing, just take the alternator off and to Autozone and take it out of the equation. Then test all the other stuff.
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Joined: Sep 2002
Posts: 2,481
From: Arlington, VA
Originally posted by ead94z28
You mean swap it with a new one and see what happens? Could it still be bad even though the readings were ok?
You mean swap it with a new one and see what happens? Could it still be bad even though the readings were ok?
Edit: Battery failure is almost 9 out of 10 times alternator charging problems. Now if you had a lot of engine mods, I'd say maybe you didn't reconnect something correctly, or you have a bad ground or something.
Last edited by scoobysnax83; Feb 19, 2004 at 12:19 AM.
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Joined: May 2003
Posts: 2,275
Looks like your alternator is bad. More precisely, the regulator built into the alternator is bad. At 14.7V I believe your over charging the battery and killing it. I am at work so I don't have my book with me but I don't believe it should be that high. That's were I'de put my money. Please keep in mind that at this moment this is a guess. Any GOOD shop should be able to tell you if that is good. I'm not sure a parts place could diagnose that with their tester or not. Try it both on the car at the parts place and then off the car at the parts place.
Perhaps someone could chime in here and let you know what is what.
Perhaps someone could chime in here and let you know what is what.