Gremlin drinking all my battery juice overnight..

Tony_SS

MalibuRacing Junkie
Apr 21, 2004
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Washington, MO
www.mac-ink.com
In my wonderful 84SS, the battery drains overnight now.. This started happening I think, after I installed a stereo, but I don't want to rule it out to that, because I unplugged the wire that I had plugged into the 'battery' fuse box and it still drained it.. unless I got a couple wires mixed up...

also, I unhooked the rear defrost switch and it still did it...

any ideas??
 

454RAT

Pro Stocker
Mar 19, 2004
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Summerville, SC
theres a couple wires that provide "constant" power, cigerette lighter stuff like that. take a look and see if theres anything pluged in taking power when key is on OFF position
 

MalibuRacing

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May 5, 2003
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Well, my first suspicion would be the new stereo installation, since that is what has changed....

You can do a test to see what is causing the drain. Get a test light. Disconnect the battery cable from the battery. Insert test light between the positive post of the battery and the positive battery cable. If there is a short or drain, the light will come on. Start pulling fuses to isolate where the drain is coming from.

It could also be a shorted diode in the alternator. disconnect battery source to it, and see if it drains overnight.
 

Jackstand

MalibuRacing Junkie
Jul 6, 2003
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KANSAS CITY, MO
MalibuRacing said:
Well, my first suspicion would be the new stereo installation, since that is what has changed....

You can do a test to see what is causing the drain. Get a test light. Disconnect the battery cable from the battery. Insert test light between the positive post of the battery and the positive battery cable. If there is a short or drain, the light will come on. Start pulling fuses to isolate where the drain is coming from.

It could also be a shorted diode in the alternator. disconnect battery source to it, and see if it drains overnight.

exactlly how to do it!
 

GreenDragginBu

MalibuRacing Junkie
Jul 10, 2003
6,293
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N.E. Ohio
Yep i have did the same thing here recently on my old mans LSC.

you can also use a amp meter and do the same...but beware if you have a high amp draw, you need a hign amp multimeter....most cars shouldnt show more than 0.9 draw.
 

Supe

MalibuRacing Junkie
May 21, 2003
15,116
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Charlotte, NC
When I hunted down the old problem on my wagon, it wasn't drawing enough juice to turn on the test light (go figure). However, it was still enough to drain the batt when sitting a few days. So originally what I did was used a single x-mas tree light bulb (the small ones), and it gave a very faint glow, which I was able to isolate at night (to an interior circuit). I had to do it on a different car, and used the lightest rated LED bulb I could get at Radio Shack. Worked like a charm.
 

MalibuRacing

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May 5, 2003
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Since it is a big enough drain to run down the battery overnight, I'm sure it will light up. On the other hand, as GDB said, it would be best to see what kind of current you're pulling using a meter. But, most handheld meters are limited to 10A, so be careful. They have a built-in fuse, so it should be protected.
 
A

Anonymous

Guest
hhhhhmmmm

i always did the negative side....guess either way that the circuit will be completed and show the same results.
rob
 

chevycopcar

Pro Stocker
Jul 19, 2004
1,494
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S. Holland, IL
Might be a long shot, but if it was converted to top post or if you have a battery with provisions for both top and side, I have seen a surprising amount of parasitic drain across the top of the battery. It happens frequently and is often over-looked. Either someone will clean the battery and it leaves residue (almost 100% of the time when someone cleans it with Coke), the battery will start leaking out of the posts, or it just gets some kind of conductive crap on the top and will bridge the terminals. A really bad case can certainly drain a battery over night, and it's very easy to check for. Just take a DMM and place one lead on the positive post and the other in various places across the top of the battery. I can't remember specifically what our given specs were, but I'd imagine if you're registering more than a tenth or so of a volt it couldn't hurt to give it the old baking soda and warm water treatment. I've seen as much as four volts! :shock:

As far as checking for amperage draw on parasitic drain, I try to enlist the help of a friendly guy over at the NTB to use his VAT machine. It only takes a second to clip the inductive clamp on it and you sure won't harm the machine. Might be worth even slipping the guy a few bucks on the side to give a shot.

-Tony
 

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