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Help! Battery isn't juicin'

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Old Dec 28, 2007 | 04:51 PM
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Help! Battery isn't juicin'

Alright, I did I crapload of research, and I found some problems similar to mine, but no solutions. My battery is a bran-new mega tron, the alternator's been replaced recently with a remanufactured one, and after I jump her and drive for a while I can turn her off and she'll start right back up, but once I go at her the next day she's completely or near dead. I checked my grounds and the negative cable has loose insulation right at the clamp. . .maybe a half inch missing, and the threads are a little bent in. Could this be my problem? I'm dreading replacing that long fudger.
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Old Dec 28, 2007 | 11:21 PM
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Sounds like a drain or short. Get a multimeter set to amps or a test lamp. Remove the negative battery cable. Touch one end of the multimeter/lamp to the negative post battery and one end to the battery cable. Do you measure any current with the car off? Ok, something is draining power. Pull the fuses one by one, and keep checking until the drain goes away. Now look at the name of the fuse you pulled. That's where the drain is.

Besides the fuses under the hood (right on top, driver's side) there are other fuses near the clutch pedal. The BTN fuse under the hood connects to all of those fuses. So if you trace the problem to the BTN fuse, that just means that you need to put the BTN fuse back and try all the fuses near the clutch pedal.

The condition of the negative cable is unrelated. Any old wire will work. A poor connection just means it'll get strained under heavy load. That comes from a loose terminal or rust/corrosion, not kinking (though kinking will make the wire more likely to snap). And if it shorts from bare insulation, that'll give off a big spark, loud bang and make a spectacular mess out of the battery if it sits there long enough (i.e., minutes or hours).

Last edited by ericgrau; Dec 28, 2007 at 11:28 PM.
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Old Dec 29, 2007 | 12:22 AM
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Use a test light. Most multimeters are only rated to 10 amps. But follow above advice otherwise.
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Old Dec 29, 2007 | 12:50 AM
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Originally Posted by whorider
Use a test light. Most multimeters are only rated to 10 amps. But follow above advice otherwise.
No, test lights don't tell you if there is a draw, or how much the draw is... it only tells you that the test light is good or bad.

A digital multi-meter is exactly what you want to test a current draw issue with... It will tell you if you have a 35mA draw or a 75mA draw... one is fine... one is too much draw. How can you tell with something as lame as a test light?

And on a current draw test, if you are drawing more than 1.5 amps you have lights on.

Just as a reference for you whorider so that you don't pass on further miss-information such as this... a headlight does not even use 5 amp... so a meter that max's out at 10 amps is going to be more than sufficient to check a current draw.
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Old Dec 29, 2007 | 02:57 PM
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ok, I'll try testing and pulling all the fuses one by one. . .but if I find one thats bad, does it mean I change that fuse, or it's somewhere in the wiring of that particular fuse conects to?
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Old Dec 29, 2007 | 05:35 PM
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if you pull the Fuse and the Current Draw Stops,then you Should be checking to see WHY That Circuit was Drawing Current in the first place..and that would be For Example,because it was Shorting or the circuit is Live (like the light remains ON,even though the Switch is Off.)
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Old Dec 30, 2007 | 09:55 AM
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What misterstyx says is generally true, but keep in mind that all cars will have a small current drain with "everything" shut off. Usually that would be about 20mA-30mA (that's milliamps not amps) or so. So, you're looking for current flow MUCH higher than that if your battery is dying overnight.
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Old Jan 14, 2008 | 05:53 PM
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I have this same problem. I wanted to know what would be a decent battery to put into my 7. Also my terminals look pretty bad and i wanted to know how I would go replacing them (if possible).

Last edited by rurounixblade; Jan 14, 2008 at 05:54 PM. Reason: spell
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Old Jan 14, 2008 | 10:31 PM
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i like that icemark, only says if the light is good or bad.
lol
a testlight is only useful if it is a yes or no question, kinda like those magic 8 *****.

peace
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Old Jan 14, 2008 | 11:05 PM
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if you re read the post there guys, you will notice one guy said remove the neg bat cable, and the other guy said use a test light, well I think that he meant remove the neg cable and use the test light to see if there is current draw between the neg cable and the bat...

although still not good to trace a problem, a test light will just show there is draw, it would be easier to pinpoint with a current amount being drawn, ie use a DMM, a light, well we allreay know there is a problem so whats the point

any way.. does the car have an alarm, sound system, what kind of electical upgrades have been done, listen by the rear of the car, is the power ant trying to go down, that i have seen a couple times, no one thinks to check the power ant.....

doubtful the neg cable is the problem, if it allows you to start the car after driving and charging the system then it's allowing the current flow, although cleaning and sealing can't hurt the situation,
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Old Jan 15, 2008 | 01:30 AM
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Originally Posted by SkyWalker
ok, I'll try testing and pulling all the fuses one by one. . .but if I find one thats bad, does it mean I change that fuse, or it's somewhere in the wiring of that particular fuse conects to?
Check what the fuse connects to. It is the thing eating up your power.
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Old Jan 15, 2008 | 05:52 AM
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Until you get it fixed, just disconnect the negative battery cable overnight so that you can just put it back on and drive the car in the morning.
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Old Jan 15, 2008 | 05:02 PM
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Originally Posted by rurounixblade
I have this same problem. I wanted to know what would be a decent battery to put into my 7. Also my terminals look pretty bad and i wanted to know how I would go replacing them (if possible).
still unanswered
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Old Jan 15, 2008 | 10:19 PM
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interstate megatron 2
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Old Jan 15, 2008 | 10:41 PM
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to replace the terminals:

Go to auto store and buy terminals for a few bucks.

Remove old terminals with socket,wrench, wire cutter, plasma cutter, or teeth.

Clean up wires, cut back insulation if needed after cutting the negative cable.

Install new terminals with socket, wrench or teeth.

I just did mine this weekend when wrapping up some small stuff. It's cake man, you'll be able to do it.
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Old Jan 15, 2008 | 10:46 PM
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Originally Posted by mike_merryguy
if you re read the post there guys, you will notice one guy said remove the neg bat cable, and the other guy said use a test light, well I think that he meant remove the neg cable and use the test light to see if there is current draw between the neg cable and the bat...

although still not good to trace a problem, a test light will just show there is draw, it would be easier to pinpoint with a current amount being drawn, ie use a DMM, a light, well we allreay know there is a problem so whats the point
No, a test light won't show you how much draw.

For example all cars have about a 35mA draw... how is a test light going to show the difference between a 35mA draw and a 100mA draw?

One is normal, and one is enough to drain a weak battery over night.

The bulb is gonna get a little brighter? And then what do you reference the brightness too? Can you tell the difference between a 35mA and a 100mA draw on a test light?

So no, a test light is useless and has no place in testing anything in a car built after the 70's.
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Old Jan 16, 2008 | 12:15 AM
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Originally Posted by Icemark
No, a test light won't show you how much draw.

For example all cars have about a 35mA draw... how is a test light going to show the difference between a 35mA draw and a 100mA draw?

One is normal, and one is enough to drain a weak battery over night.

The bulb is gonna get a little brighter? And then what do you reference the brightness too? Can you tell the difference between a 35mA and a 100mA draw on a test light?

So no, a test light is useless and has no place in testing anything in a car built after the 70's.
well I never said the light would show an amount of current draw, just that there was one, if you connect a test light and its off, well guess what there is no draw, and if you hook it up and the light comes on, gee i guess there is a draw
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