battery drain saga continues
Thread Starter
Instructor
Joined: Apr 2007
Posts: 215
Likes: 1
battery drain saga continues
Ok. Still chasing this thing. I disconected the negative battery cable from the battery, hooked up a jumper wire from the battery terminal to one side of a volt meter, the negative battery cable to a jumper wire to the second lead on the volt meter and have 12.36 volts. I pulled every fuse and breaker from the fuse pannel. I still have 12.36v I unplugged all the connectors on both the doors and the connectors under the power seats. Then I unplugged every relay and unplugged every connector behind the DIC. The digital dash is out of the car being rebuilt again. What else can I check?
Pro
Joined: Aug 2007
Posts: 600
Likes: 0
From: been there done that
if i read your post correctly,you're checking battery voltage?i'm assuming you're looking for a drain on your battery.if so you need to hook up an amp meter on the positive side of the battery.then when you pull your fuses etc you'll be looking for a 'drop' in the amperage shown on the meter.i'm guessing here but the draw should be less than 1 amp.if i'm mistaken hopefully someone with a bit more experience will chime in.DO NOT TURN ON THE IGNITION AS IT WILL MOST LIKELY FRY YOUR METER.hope this helps.chuck
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
You don't say that you have disconnected any of the fusible links. As long as there is current (amperage) flowing you should expect it to be battery voltage unless you get down to one last draw and it is one of high resistance.
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Thread Starter
Instructor
Joined: Apr 2007
Posts: 215
Likes: 1
CFI, your saying I will have 12v between neg. terminal and cable like I described above? I value your opinion because you helped me out many times. I am confused now. Old school was no voltage between terminal and cable.
Instructor
Joined: Mar 2005
Posts: 216
Likes: 3
Buy a seliniod,600amp 12volt continuas coil and all your problems are gone, not to mention a great theif device, mine is operated by the ciggeretter lighter, I drive my 86 about once a month and one thing i know for sure is my battery is just is strong as went i shut it off, not to mention just drive 2 blocks and the battery is fully charged again. Let me know if you want to know where to get one, dave
Team Owner
Joined: Mar 2001
Posts: 54,124
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From: Cincinnati, Oh USA
First of all you do not measure battery leakage current with a voltmeter. If you are using a VOM (voltmeter ohmeter milliammeter), you connect the test leads in series between one battery cable and the battery terminal you took the cable off of. The VOM must be set up to measure current (amps or milliamps). Its best to start of in amps, and most VOM test meters require you to plug the positive test lead into a separate jack marked (AMPS). GM says leakage current should not be higher than 50 milliamps (.05 amps), my 87 draws 27 ma. and I do not have any problems with discharged battery. Watch the ammeter while you remove fuses one at a time and look for a dramatic drop in current.
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Thread Starter
Instructor
Joined: Apr 2007
Posts: 215
Likes: 1
thanks jfb. I am using a blue-point EEDM503B multimeter set on 20 DCV. black lead is plugged into COM 24 max fused port and red is plugged into V omega 1k max. jumped between negative terminal and negative cable and drawing 12.36v.
Race Director
Joined: Jan 2006
Posts: 10,039
Likes: 0
From: CA
I've read your other posts on this,but maybe I missed exactly what this battery drain you have is affecting.After so many days,months,is it so bad that the car will not even crank over?How long does it take while the car is not operational before the battery will not allow you to actually start? things are a little different for me.I drive mine almost everyday,and have experienced no problems.The current draw from the ECM should be minimal.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
stick105,
You cannot measure current coming out of the battery when your VOM is set on volts. You must set your VOM on AMPS!!!!!!!!!!! and I believe you should connect your test leads to the two outside jacks on your meter. The two inside jacks are for measuring volts and ohms. Read the instruction manual that came with the meter to see how to measure AMPS.
When you are done measuring current , be sure to move your test leads back to the two inside jacks. If you connect your meter set up for amps across the battery posts,you will damage your meter!!
You cannot measure current coming out of the battery when your VOM is set on volts. You must set your VOM on AMPS!!!!!!!!!!! and I believe you should connect your test leads to the two outside jacks on your meter. The two inside jacks are for measuring volts and ohms. Read the instruction manual that came with the meter to see how to measure AMPS.
When you are done measuring current , be sure to move your test leads back to the two inside jacks. If you connect your meter set up for amps across the battery posts,you will damage your meter!!
Advanced
Joined: Jun 2007
Posts: 71
Likes: 0
From: Tucson Az
Stick105 is not trying to measure the current coming out of the battery. He is measuring the voltage drop across the circuit. The problem with this method is EVERYTHING must be off. This includes the clock and memory in the radio. If ANYTHING is on, you will have a voltage drop of around the 12VDC that you are seeing. All doors must be closed. Which is another problem since the doors have a delay turning off the dome lights. If your fuse block is behind the passenger door (at least on mine it is) this way of testing will take quite some time waiting for the dome lights to power down each time. This method works well on the older vehicles, but not so well on the corvettes. So the best and easiest way to check your system is the way “jfb” has stated above.
Thread Starter
Instructor
Joined: Apr 2007
Posts: 215
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Thanks for all the info guys. I am lost with electrical problems. jfb thanks for the detailed info. I appreciate it greatly. I will mess arround with it again on Sunday. Now I gotta dig out the instructions for my meter. Thanks again. Once I make the meter change from volts to amps, then I jump them between negative terminal and cable or positive termonal and cable?
Team Owner
Joined: Jan 2003
Posts: 20,315
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From: Summerland B.C. Canada
Use the neg cable, it's safer.
Racer
Joined: Apr 2006
Posts: 419
Likes: 1
From: Kelso WA
One more thing to be aware of is that the ammeter is protected by a fuse that can be blown if you exceed the amp rating for the meter. Most cheap voltmeters will only measure up to 2 or 300 milliamps. You probably need something that will measure up to 10 amps or so. One lead from your meter goes to the battery terminal (-) and the other lead goes to the - cable for the battery after you've removed it from the battery. If you are measuring no current draw, then you probably blew the fuse and your system is drawing more current than the meter can measure. Once you blow the fuse, your ohmmeter probably can't be used to check the fuse. Your meter should have an amp scale on it that will tell you what the maximum current can be.
Le Mans Master
Joined: Oct 2004
Posts: 5,841
Likes: 19
From: CLT, North Carolina
Please take a minute to fill out you profile. I looked to see what year your car was but no info is there. On later VATS equipped C4's you will always have a current draw that will indicate 12 volts on a voltmeter. This does not tell you what you need to know. With a key left in the ignition the computers are awake and around 250 mills of current is flowing. This is enough to run the battery down on a car that is not driven every day. Even with the key out computers still draw around 50 mills, this is significantly less but for cars that are driven only occassionally battery rundown is still a problem. For cars that spend a lot of time in the garage a float charger is recommended to keep the battery fully charged. Or disconnect the battery but you will lose your presets.