Battery Drain
Thread Starter
Instructor
Joined: Oct 1999
Posts: 145
Likes: 0
From: San Francisco, CA, USA
Battery Drain
I've go a stock 85 that appears to have a battery drain somewhere. If I leave it for a couple weeks the battery is totally dead (yeah, I know, don't leave it for a couple weeks :lol: ).
What's the best way to track down this problem?
What's the best way to track down this problem?
Melting Slicks
Joined: Feb 1999
Posts: 3,261
Likes: 9
From: sonoma ca
Re: Battery Drain (OnDVirg)
If your gonna leave it for that length get a trickle charger or disconnect the battery.
If it does it consistently it may have a negative effect on your alternator. :cheers:
If it does it consistently it may have a negative effect on your alternator. :cheers:
Instructor
Joined: Apr 2001
Posts: 187
Likes: 0
Re: Battery Drain (OnDVirg)
I have the same problem with my 85 but it goes dead after two days. Battery & alternator are fine. Burned my linkable fuse at the starter last time and this time to. Its going to the dealer tomorrow to find the short or what ever. Got the KY because here it comes. :crazy:
Melting Slicks
Joined: Mar 2001
Posts: 2,107
Likes: 0
From: Austin TX
Re: Battery Drain
You can make your own trickle charger cheaply and charge without poping the hood.
Go to Radio Shack (or anyplace that sells 12V DC wall power adapters). Pick one that has 300mA or higher rating @ 12VDC. Also buy a cigarette lighter connector.
Cut off the end on the wall adapter and wire to the cig connector. Plug in the power adapter and check for correct polarity (tip is +, side is -). Should read over 12V DC also.
Plug it in the cig lighter on the vette whenever you want to charge. I have mine hanging from the ceiling in the garage. I use a pretty thin wire (equiv 22 awg speaker wire) so I can close the door without any problems. The current from the adapter is low, so there are no fire hazard problems if there is a short or failure.
It keeps the battery healthy and always ready to go. Draining the battery down often will permanently damage the battery - this is a good way to keep the battery fresh.
Oh yea, this is good for people that are always working on the car. It prevents the battery from running down i.e. keeping the door open (dome light), working on the stereo, frequent starts, etc.
[Modified by pzoom, 9:50 AM 7/16/2002]
Go to Radio Shack (or anyplace that sells 12V DC wall power adapters). Pick one that has 300mA or higher rating @ 12VDC. Also buy a cigarette lighter connector.
Cut off the end on the wall adapter and wire to the cig connector. Plug in the power adapter and check for correct polarity (tip is +, side is -). Should read over 12V DC also.
Plug it in the cig lighter on the vette whenever you want to charge. I have mine hanging from the ceiling in the garage. I use a pretty thin wire (equiv 22 awg speaker wire) so I can close the door without any problems. The current from the adapter is low, so there are no fire hazard problems if there is a short or failure.
It keeps the battery healthy and always ready to go. Draining the battery down often will permanently damage the battery - this is a good way to keep the battery fresh.
Oh yea, this is good for people that are always working on the car. It prevents the battery from running down i.e. keeping the door open (dome light), working on the stereo, frequent starts, etc.
[Modified by pzoom, 9:50 AM 7/16/2002]
Thread Starter
Instructor
Joined: Oct 1999
Posts: 145
Likes: 0
From: San Francisco, CA, USA
Re: Battery Drain (pzoom)
I've thought about the trickle charge option, I usually don't leave the car sit for more than a couple days, except when I'm out of town. Is this a common occurance to have the battery drain after only 2 weeks? I've never had another car where this was a problem... :cool:
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Battery Drain (OnDVirg)
Your battery shouldn't go dead after sitting for two weeks. Remove the negative cable and put an ammeter (VOM) from the battery to the neg cable to measure the current out of the battery. Start at a high current setting so the courtesy lights don't pin your ammeter and switch it to lower full scale current after they go out to find out what the leakage current is. I measured my 87 recently and it was 26 ma. The drain should be under 50 ma. If not, then watch the ammeter and pull the fuses one at a time and look for a dramatic drop in current. This will find the circuit that is drawing the excess current. There are about 10 fusible links on the jump start terminal by the battery and those can be removed if no circuit with a fuse is drawing excess current. Good luck.
Intermediate
Joined: May 2002
Posts: 26
Likes: 0
From: Mililani HI
Re: Battery Drain (jfb)
jfb, I followed your advice as stated in your post and also checked out my alternator as per your instructions on a previous thread and everthing checked out o.k. I could never find what caused my battery to totally drain overnight. I am now thinking that I might have a faulty relay - any way to test them?
Thanks for all your advice! :cheers:
Thanks for all your advice! :cheers:
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Battery Drain (OnDVirg)
Relay contacts can stick and then later unstick and the relay work fine. If you didn't measure high leakage current with your ammeter, then you probably have an intermittent which you will only be able to find when it becomes active again. If you have a stuck relay, then you can try unplugging the ones by the fuses and see if the current drops. Otherwise you will have to determine what circuit the leakage current is in and if there is a relay in that circuit, measure the relay coil voltage and see if it is or is not energized, if not then measure the volts on the circuits that are turned on by the relay contacts and see if you have a stuck relay contact and replace the defective relay.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Battery Drain (OnDVirg)
Relay contacts can stick and then later unstick and the relay work fine. If you didn't measure high leakage current with your ammeter, then you probably have an intermittent which you will only be able to find when it becomes active again. If you have a stuck relay, then you can try unplugging the ones by the fuses and see if the current drops. Otherwise you will have to determine what circuit the leakage current is in and if there is a relay in that circuit, measure the relay coil voltage and see if it is or is not energized, if not then measure the volts on the circuits that are turned on by the relay contacts and see if you have a stuck relay contact and replace the defective relay.
What leakage current did you measure?
What leakage current did you measure?
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Battery Drain (pascualjr)
38 ma. will not discharge a battery in 2 weeks. Particles of battery plates flake off and settle on the bottom of the battery and finally get high enough to touch the plates and cause a conducting path which discharges the battery. If your battery is near the end of its guarantee period, then this may be what is happening. You can test for this by fully charging the battery and leave it sit disconnected. The battery voltage is an indicator of the state of charge. A fully charged lead acid battery has 13.2 volts across it and discharged is 12.0 volts. These volts are measured with the battery sitting for 24 hours. If you can check on successive days and the terminal volts is dropping noticeably, then your battery is at the end of its life and I would replace it.
