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  #1  
Old 07-23-2010, 01:22 PM
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Am I checking battery draw correctly?

I have a drain overnight....Trying to figure it out today.

Battery holds charge overnight when disconnected from the system. 12.68v held for over 10hours.
Engine running gets me 13.88v (battery was low during this test...not sure if that affects readings or not).

Load tested battery and looks OK right? :






Then I checked draw, but 9mA seems far too low...Maybe I am doing something wrong here?

I have my DMM set to COM and 20A. I'm relatively new to all this type of stuff.



Thanks,
Robert

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Old 07-23-2010, 01:43 PM
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On some meters the red probe has to be moved to a different hole. I don't know about that meter. Otherwise it looks like you are doing it right. You could try the mA setting also.
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  #3  
Old 07-23-2010, 02:11 PM
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I have the probe in the 20A socket...so it is in the right place.

I just thought that I would be seeing more then 9mA? Maybe I have an intermittent drain?
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Old 07-23-2010, 05:37 PM
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Ok did some more testing. Here is where it gets weird:

Engine ON: 13.95v
Engine ON + A/C: 13.82v
Engine ON + A/C + Radio/Amp/Sub high: 13.70v
Engine ON + A/C + Radio/Amp/Sub High + Lights: 12.65v
Engine ON + A/C + Lights: 12.8v
Engine ON + Lights: 12.89v
Engine ON + Lights + Fogs: 12.80v


I think this issue is to do with the lights....My warning bulb dummy light is on, but I thought that was something separate...maybe it IS in fact related?

Any ideas?
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  #5  
Old 07-23-2010, 08:56 PM
LarryBible
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I can't see how you've connected the leads. An Ammeter must be connected in series. Set up your meter for Ammeter with leads in the right connectors. Remove a battery cable from the post and put one lead on the battery and the other on the post. This puts the meter in series. Then with everything turned off, see how much current it draws.

Hope this helps.
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  #6  
Old 07-23-2010, 09:05 PM
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That is how I have it set up.

DMM(+) on the (+) battery terminal, and the DMM(-) on the (+)battery cable.
DMM Probe leads: Red = 20A and Black = COM

Everything should be in series.

Either way, why are my lights taking such a huge hit voltage-wise (over 1.0v), yet no other accessories affect it by more then 0.20v?
Does this indicate a failing alternator, or some sort of excessive electrical draw problem in the lighting system?
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  #7  
Old 07-24-2010, 02:15 AM
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Read this thread M-103: too many issues for the title... It may help. You should remember it! You weighed in there.

When are you gonna make it to one of our drag strip days? The next one is in Sept.: Anybody up for some 1/4 mile action?
Regards, Eric

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Last edited by 400Eric; 07-24-2010 at 02:26 AM.
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