C20 - draining battery - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cjlinkster · 07-25-2011, 08:51 PM

My battery keeps draining after 3~4 days.

I have read other posts here on how-to track down the issue, so this is what I tried. I disconnected the ground from the battery and used a voltmeter between the negative post and wire. I am getting a steady reading of 12.5v. I then pulled each fuse at a time and verified the voltmeter.

I am still getting a reading of 12.5v at the meter!!?? My truck is a factor camper special. Could something be going on with the thick camper plug wire? Is this wire DC or is it connected to a power converter?

Any suggestions?

Dan1969 · 07-25-2011, 09:09 PM

Pretty much everything on your truck is DC. if the truck keeps draining the batter I would look for the alternator not charging it; do the post removal thing while the truck is running just to be sure even if your amp meter or volt meter are reading properly.

*72lb4x4* · 07-25-2011, 09:15 PM

That's not how you check. You normally don't open a circuit and put a voltmeter in as you describe. Thus you get meaningless results.

Try putting a test light where you have the voltmeter.

cjlinkster · 07-25-2011, 09:28 PM

Its actually a multimeter that I am using in my testing (not a only voltmeter).

cjlinkster · 07-26-2011, 08:57 PM

I retested the fuse box again today.

This time I had my multimeter setup to use the 10amp unfused setting. Measuring current drain is showing .001 (in the 10a setting), so it doesn't seem like too much, but I can't seem to determine the cause of the drain.

Any ideals? Is that enough current to be worried about?

Dan1969 · 07-26-2011, 09:28 PM

Is your alternator working properly...

jojoman · 07-26-2011, 09:38 PM

My battery Kept doing the same thing but I had a bad alternator plug it had crusted out so it The wires had not been conducting right
Posted via Mobile Device

motornut · 07-26-2011, 10:05 PM

what does it read charging

*72lb4x4* · 07-26-2011, 10:13 PM

Quote:

Originally Posted by cjlinkster

Its actually a multimeter that I am using in my testing (not a only voltmeter).

You don't use a multimeter set on Volts that way either.

1mA hardly seems like it would drain the battery in a few days.
With the meter set to measure current and connected properly, you can start popping fuses again. You may want to start by disconnecting the harnesses at the FW connector and looking for a change in current.

What's the voltage on the battery with the engine off?
What's the voltage on the battery with the engine running?
What's the voltage on the battery with the engine running at about 2000RPM?

07-25-2011, 08:51 PM	#1
cjlinkster Registered User Join Date: Jun 2011 Location: Atlanta ga Posts: 150	C20 - draining battery My battery keeps draining after 3~4 days. I have read other posts here on how-to track down the issue, so this is what I tried. I disconnected the ground from the battery and used a voltmeter between the negative post and wire. I am getting a steady reading of 12.5v. I then pulled each fuse at a time and verified the voltmeter. I am still getting a reading of 12.5v at the meter!!?? My truck is a factor camper special. Could something be going on with the thick camper plug wire? Is this wire DC or is it connected to a power converter? Any suggestions? __________________ 1984 C20, 454, 4 speed named "Gold Member"

07-25-2011, 09:09 PM	#2
Dan1969 Registered User Join Date: Jun 2011 Location: OK Posts: 76	Re: C20 - draining battery Pretty much everything on your truck is DC. if the truck keeps draining the batter I would look for the alternator not charging it; do the post removal thing while the truck is running just to be sure even if your amp meter or volt meter are reading properly.

07-25-2011, 09:15 PM	#3
72lb4x4 Account Suspended Join Date: Jul 2006 Location: DFW Posts: 1,427	Re: C20 - draining battery That's not how you check. You normally don't open a circuit and put a voltmeter in as you describe. Thus you get meaningless results. Try putting a test light where you have the voltmeter.

07-25-2011, 09:28 PM	#4
cjlinkster Registered User Join Date: Jun 2011 Location: Atlanta ga Posts: 150	Re: C20 - draining battery Its actually a multimeter that I am using in my testing (not a only voltmeter). __________________ 1984 C20, 454, 4 speed named "Gold Member"

07-26-2011, 08:57 PM	#5
cjlinkster Registered User Join Date: Jun 2011 Location: Atlanta ga Posts: 150	Re: C20 - draining battery I retested the fuse box again today. This time I had my multimeter setup to use the 10amp unfused setting. Measuring current drain is showing .001 (in the 10a setting), so it doesn't seem like too much, but I can't seem to determine the cause of the drain. Any ideals? Is that enough current to be worried about? __________________ 1984 C20, 454, 4 speed named "Gold Member"

07-26-2011, 09:28 PM	#6
Dan1969 Registered User Join Date: Jun 2011 Location: OK Posts: 76	Re: C20 - draining battery Is your alternator working properly...

07-26-2011, 09:38 PM	#7
jojoman Registered User Join Date: Jul 2010 Location: Houston,Tx. Posts: 241	Re: C20 - draining battery My battery Kept doing the same thing but I had a bad alternator plug it had crusted out so it The wires had not been conducting right Posted via Mobile Device

07-26-2011, 10:05 PM	#8
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: C20 - draining battery what does it read charging __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350



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