Author Topic: How to track down a parasitical electrical drain?  (Read 931 times)

Offline DocMel

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How to track down a parasitical electrical drain?
« on: November 15, 2013 - 05:41:57 PM »
Folks 

I have just started to get a drain on my battery that I didnt have before.   

The car now can sit for about 5 days or so and the battery will be almost dead

The battery checks out fine, so............

Outside of taking one fuse out at a time and waiting for the battery to die again to see at least which circuit is causing the drain, any other way to narrow down what circuit is at fault?

In other words, a faster way to narrow down which circuit is at fault?




Offline Chryco Psycho

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Re: How to track down a parasitical electrical drain?
« Reply #1 on: November 15, 2013 - 06:03:42 PM »
With the fuse removed you can put an ammeter across the fuse terminals to see if there is a load

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Offline DocMel

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Re: How to track down a parasitical electrical drain?
« Reply #2 on: November 15, 2013 - 07:52:13 PM »

Ouch:  Thats so obvious I cant believe I didn't think about that   
Thanks.   Ill give it a shot for sure

Offline Chryco Psycho

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Re: How to track down a parasitical electrical drain?
« Reply #3 on: November 15, 2013 - 10:17:55 PM »
JUst touch it momentarily & see if the neddle deflects , often the load can exceed the meter capacity , I prefer to use analog meters over digital , easier to see what is going on  :2cents:

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Offline rUNCHARGER

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Re: How to track down a parasitical electrical drain?
« Reply #4 on: November 15, 2013 - 11:21:33 PM »
I had a drain like that once, it turned out to be the seat belt buzzer, but it could be a dozen items.

Sheldon

Offline dodj

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Re: How to track down a parasitical electrical drain?
« Reply #5 on: November 16, 2013 - 08:28:29 PM »
If you have a friend with a 'clip on' ammeter, you can figure it out in a couple minutes. Unfortunately, they are pricey to buy. But you can still do it like CP says with a regular ammeter. Start by putting the ammeter in line with one of the battery connections first to see what kind (size) of drain you have. Then it is a matter of dividing up the electrical ccts, opening and inserting the ammeter to see where the current is going.
I agree with you CP with analog meters as far as pulsing currents go, but with a small battery drain, it is likely a small load (current) that is draining the battery  :2cents:
Scott
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2007.5 3500 6.7 Cummins Diesel, Anarchy tuned.
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