Battery Drain
Thread Starter
Intermediate
Joined: Jul 2021
Posts: 29
Likes: 1
From: Deltona, FL
Battery Drain
I posted a similar post yesterday but don't see it listed here.
I am dealing with battery drain for my C-5 which I understand is a common problem. I replaced the battery I bought at O Reileys with an Optima Red Top. It came with some instructions on how to measure and locate the source of battery drain. Disconnect one lead from the terminal in this case I chose the black. Then using a multimeter to measure the voltage by placing one meter lead on battery terminal and the other on the disconnected terminal lead. The literature said it should be no more than 100 mv. My millivolt readings went off scale. When a switched to a 15 volt setting the reading I got was between 9.5 and 10 volts. I started removing fuses one at a time and then checked meter for voltage drop. No drop occurred after checking all major fuses in the box under the hood. Next I am moving on the the fuse box inside the car on the passenger side.
Has anybody else had a similar experience and can give advice on a likely cause and fuse I should check out? Could this be just a short or frayed wire somewhere?
I don't have any after market electrical equipment that might cause this drain.
I posted a similar thread yesterday but I don't see it when I look over the listed threads from the last few days. I did do a search for battery drain issues on this site but nothing I read applied and I was given references to all Corvette years. Mine is a 2000 with a six speed manual transmission.
Todd
I am dealing with battery drain for my C-5 which I understand is a common problem. I replaced the battery I bought at O Reileys with an Optima Red Top. It came with some instructions on how to measure and locate the source of battery drain. Disconnect one lead from the terminal in this case I chose the black. Then using a multimeter to measure the voltage by placing one meter lead on battery terminal and the other on the disconnected terminal lead. The literature said it should be no more than 100 mv. My millivolt readings went off scale. When a switched to a 15 volt setting the reading I got was between 9.5 and 10 volts. I started removing fuses one at a time and then checked meter for voltage drop. No drop occurred after checking all major fuses in the box under the hood. Next I am moving on the the fuse box inside the car on the passenger side.
Has anybody else had a similar experience and can give advice on a likely cause and fuse I should check out? Could this be just a short or frayed wire somewhere?
I don't have any after market electrical equipment that might cause this drain.
I posted a similar thread yesterday but I don't see it when I look over the listed threads from the last few days. I did do a search for battery drain issues on this site but nothing I read applied and I was given references to all Corvette years. Mine is a 2000 with a six speed manual transmission.
Todd
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,597
Likes: 4,057
From: Cape Coral, Florida
You posted it in the Tech section yesterday !!…I posted this video for you to watch…you are supposed to be measuring in “milliamps” between the battery post and disconnected cable !!…once you perform the proper testing procedure if you still have a draw you can disconnect the B+ cable at the alternator …a bad diode in the alternator can cause a drain !!
Last edited by C5 Diag; Jul 7, 2021 at 07:31 PM.
Drifting
Joined: Sep 2009
Posts: 1,862
Likes: 594
From: Prescott, Arizona
I had that symptom, I pulled the seat circuit breakers and the drain stopped. I later replaced the Driver side seat switch which solved the drain.
But it could be a bad alternator diode or--- something else. Pulling seat circuit breakers is simple enough to try first.
If that does not solve the problem, post #3 above is how you find the problem.
But it could be a bad alternator diode or--- something else. Pulling seat circuit breakers is simple enough to try first.
If that does not solve the problem, post #3 above is how you find the problem.
Melting Slicks
Joined: Nov 2014
Posts: 3,399
Likes: 1,339
From: Havre de Grace Maryland
I suspect I will get a bunch of negative replies from the purest that will opine that everything has to be functioning properly. OK I get it but here is my DIYS fix: If not the battery, just buy a negative battery easy disconnect and be done with it. That is what I have done just in case I have a similar issue,. The C5 has so many electrical anomolies that I looked for a simple solution to a voltage drain.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,597
Likes: 4,057
From: Cape Coral, Florida
I suspect I will get a bunch of negative replies from the purest that will opine that everything has to be functioning properly. OK I get it but here is my DIYS fix: If not the battery, just buy a negative battery easy disconnect and be done with it. That is what I have done just in case I have a similar issue,. The C5 has so many electrical anomolies that I looked for a simple solution to a voltage drain.
