Parasitic draw on car battery?

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  #1  
Old 10-30-16, 07:03 AM
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Parasitic draw on car battery?

I have a 1996 Toyota starlet and the battery after fully charged will run down after a day. I have looked at parasitic draw tests on YouTube, putting the multimeter in series with the negative battery cable and negative battery terminal and having all the doors and lights of and the multimeter on the 10A DC scale. But I can't get any reading. Was looking for advice to see if I'm doing anything wrong.

Any help would be much appreciated
 
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  #2  
Old 10-30-16, 07:18 AM
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Open the drivers window. Remove the negative battery cable and connect the meter between negative terminal of the battery and the cable. Turn on the dome light. If the light goes on and you read an amp or two all is good. If the light doesn't go on and you get no reading then the internal fuse of your multimeter is probably blown. Most multi-meters have a fuse in series with the high current range. It's possible you blew the fuse when you first connected the multimeter if there is a draw over 10 amps or you did something like turn the headlights on.

A safer way to do this type of test without possibility of damaging the meter is to use a DC current shunt, such as this one:

https://www.amazon.com/SODIAL-Analog...+current+shunt

You insert that (temporarily) in series with the negative battery cable, and then measure DC voltage across the shunt. You may melt the shunt if you try to start the car with it in place, but any other load should be less than 100 amps.
 
  #3  
Old 10-30-16, 07:21 AM
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Modern cars all have a small amount of parasitic draw. Usually in mitli amp range. Need a meter that can read small amp draw. This draw is not enough to discharge a battery overnight. Get battery tested on a load tester out of car.
 
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Old 10-30-16, 08:57 AM
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the battery after fully charged will run down after a day.

So how actually old is the battery itself?
 
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Old 10-30-16, 10:11 AM
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Battery is only a couple years old
 
  #6  
Old 10-30-16, 10:40 AM
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The multimeter I have is a draper 60792. Can anyone tell me if this multimeter will do my Job
 
  #7  
Old 10-30-16, 10:44 AM
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That meter is fine for up to 10 amps. If you need to read more than 2 amps you use the common and 10 amp jacks for the leads. If less than 2 amps you use the common and V-OHM-AMP jacks for the leads.
 
  #8  
Old 10-30-16, 11:01 AM
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If after attempting to run down the problem by the above advice using a meter, I'd start pulling fuses to basic things like power windows, radio, etc. for a few hours at a time & see if you can trace it down that way.

Lets say, if you pull the fuse to the power windows & there is no voltage drop & the battery is still up the next time you check it. The power windows would be the area to trace down.

Check battery voltage, pull a fuse, check voltage, etc, etc.... even if you have to pull the fuse for a 1/2 day or even a full day & then check battery voltage, etc.
It may take a few days to run it down like this but, again, if worse comes to worse, that's what I'd do.
 
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Old 10-30-16, 11:43 AM
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Battery a couple years old I would have it tested on a bench tester. In 40 years of auto work have seen many battery's fail in less time. Do not trust hand held testers.
 
  #10  
Old 10-30-16, 11:45 AM
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Especially after having checked with the meter and not found a current drain "only a couple years old" sounds fuzzy to me. Have you checked the battery to make sure it is good? And by check the battery I mean... check the battery. Even a battery "a couple years old" can go bad. Start with the simple stuff first. Confirm, not guess, that the battery is good before moving on to more nebulous things like tracking down a current drain.
 
  #11  
Old 10-30-16, 12:29 PM
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Is it possible to measure the voltage drop over the fuses to find any voltage activity over them to find the bad circuit
 
  #12  
Old 10-30-16, 01:41 PM
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Look, OP. You BEST bet is to bench test battery. They DO go bad in few years. Esp if terminals were not clean and lubricated and sealed and clamps not seated right.
 
  #13  
Old 10-31-16, 05:22 AM
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"Is it possible to measure the voltage drop over the fuses to find any voltage activity over them to find the bad circuit"

I don't think you are "electrically minded" ... there is no voltage drop over fuses unless they are open.
You would probably be better off taking your car to a knowledgeable mechanic for this problem.

Good luck.
 
  #14  
Old 10-31-16, 05:31 AM
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Perhaps I shouldn't of used the term voltage drop. But if I have the probes of the multimeter on the contacts of the fuse. The fuse or circuit which has the current draw should have a voltage passing over it due to the relationship between voltage, current and resistance, the voltage will be very small- in the millivolt scale but this method should tell me which circuit has the current draw
 
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Old 10-31-16, 09:01 AM
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I have found voltage drops in all sorts of places. Included fuse banks. 12volts isn't much and all it takes is a slight bit of corrosion to cause resistance. When on a bug hunt you really can't afford to leave anything off the list. I start at the source. The battery and verify 100% that it is good.

I had a current draw in a 2001 BMW Z. It may have been a normal draw but it was enough to prevent the car from starting if it sat 2-3 weeks without running. On my first pass I did not find a draw. Pulling my hair out I started over again and left the meter hooked into each circuit for a couple minutes and watched. Sure enough part of the alarm system was tied in with the dash instruments. Every minute and a half it would power up to about an amp and stay powered for a minute before shutting down again.
 
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Old 10-31-16, 10:41 AM
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"Perhaps I shouldn't of used the term voltage drop. But if I have the probes of the multimeter on the contacts of the fuse. The fuse or circuit which has the current draw should have a voltage passing over it due to the relationship between voltage, current and resistance, the voltage will be very small- in the millivolt scale but this method should tell me which circuit has the current draw"

Yes and no
That is the last method I would use as a trouble-shooting technique in this case.
 
  #17  
Old 10-31-16, 02:37 PM
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I get my battery bench test so I can isolate the fault. To make sure is a bench test is essentially a load test
 
  #18  
Old 10-31-16, 03:39 PM
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Yep, charge your battery fully and get it load tested, then buy a new battery.
 
  #19  
Old 11-01-16, 06:08 AM
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Just to put a finer point on it, DON'T accept a battery test in or out of the car using a hand-held tester--usually offered for free at auto parts stores. You want a test where the battery is tested under full load.

Last winter I wasted many hours trying to locate a "parasitic loss" when the real problem was a ONE year old battery that Autozone kept assuring me was testing perfect.
 
  #20  
Old 11-01-16, 07:58 AM
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In addition to selecting the proper setting and scale, most meters require you to switch the location of the positive probe to measure higher currents. Perhaps your positive/red probe is still plugged into the lower current/voltage jack? And try switching between 10A and 200m on your dial. If you are way under 10A, you won't register a reading, and if you are way over 200mA, you won't see anything either. Note that with the positive probe plugged into the 10A jack, you can still measure small currents. 10A is the maximum rating for that jack. 200mA is the maximum for the other, which I wouldn't use. You could draw nearly an amp or more when you first connect the battery, so perhaps you blew the fuse on the 200mA jack. Try the 10A jack if you haven't already and adjust the dial between 10A and 200mA until you get a reading.

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  #21  
Old 11-02-16, 03:12 AM
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Cheers mate, I have replaced my 200mA fuse and am getting the battery load tested
 
  #22  
Old 11-02-16, 12:12 PM
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So I replaced the fuse in my multimeter, haven't got the battery tested yet, but done the parasitic test with the probes in the correct port and the settings and absolutely no change on the multimeter whatsoever, meaning it must be the battery. One thing of note is a slight spark was created when the multimeter was attached. It is probably nothing but if it is can someone tell me
 

Last edited by Ruddock984; 11-02-16 at 12:12 PM. Reason: Mistake
  #23  
Old 11-02-16, 12:32 PM
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Did you do the test I described in the first reply to your post? That will tell you if your meter is working. I recommend you do the test using the 10 amp range. It will be plenty sensitive enough to see the current flow when you turn on the dome light.

That spark could certainly have resulted in your fuse blowing again....

But still concur with others that a battery test is in order.
 
  #24  
Old 11-02-16, 04:36 PM
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I just learned from my bro who had the car before me had replaced the battery and before that the issue still happened
 
  #25  
Old 11-03-16, 03:19 PM
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Red, not trying to tell you what to do or be mean.
You spent how many days and posts on assumptions, instead of testing the battery? It's not even that hard to do - drive to parts store, with tools, pull it out, let them bench test it, drop it back in. 15 minutes and minimum effort.
 
  #26  
Old 11-04-16, 05:04 AM
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So got the battery tested and basically it's a piece of crap so I'm getting a new battery which hopefully fixes my issue
 
  #27  
Old 11-04-16, 05:50 AM
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Never forget the simple stuff. I can't tell you how many times I've gone chasing after oddball things only to have the problem be something really basic that I should have checked first.
 
  #28  
Old 11-04-16, 06:14 AM
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"I just learned from my bro who had the car before me had replaced the battery and before that the issue still happened"

This is a confusing, contradicting piece of information .....
 
  #29  
Old 11-07-16, 04:49 AM
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So I bought a battery and did a draw test and got 0.10A and got this down to zero after pulling the dome light fuse. Was quite surprised as I have never seen the dome light on in the car overnight, must be a fault some but for now I don't need the dome light
 

Last edited by Ruddock984; 11-07-16 at 04:51 AM. Reason: Additional information
  #30  
Old 11-07-16, 07:04 AM
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That's a normal load for that circuit when "everything is off". The dome light circuit might have several other loads on it because it's a battery feed that's always on.
 
  #31  
Old 11-07-16, 07:20 AM
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So I bought a battery and did a draw test and got 0.10A and got this down to zero after pulling the dome light fuse. Was quite surprised as I have never seen the dome light on in the car overnight, must be a fault some but for now I don't need the dome light
100 mA is normal and is negligible. You aren't drawing zero current. Put the meter on the 200m scale and you'll see exactly how much you are still drawing with "everything off". Remember, your ECU draws current always.

To put things in perspective, if you have a 50Ah battery and have a constant draw of 100mA, it would take nearly 21 days to deplete the battery.
 
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