Battery drain????
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 1,154
Likes: 1
From: St Augustine FL
Battery drain????
89 coupe 92,000 miles. I replaced the key ignition swithc assembly over thanksgiving because the car would not read the security pellet in the key. The wires were broken and mangled on the switch. I have not driven or started the car since replacing the switch. I went to start the car the other day and the battery was dead as a door nail. I jump the car and it started right up. I let the car run for about 2 hours to charge the battery. the car has sat for a week. I went to start the car again. The battery is dead as a door nail again. Jumped it and fired right up. Do I have a battery drain problem or is it just a bad battery that needs to be replaced????? I have no idea how old the battery is and it does not appear to be swollen.
Team Owner
Joined: Jan 2003
Posts: 20,290
Likes: 239
From: Summerland B.C. Canada
You can pull the battery and have it tested or pull the neg battery terminal and test for current draw, after courtesy lights have timed out.
One of those tests should help answer your question.
One of those tests should help answer your question.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Measure the current, GM says it should not exceed 50 milliamps. My 87 draws 27 ma. and I have no problems. Don't leave your key in the ign as this keeps the antitheft circuit on. At night see if you can see the vaniity mirror lights on or the door map lights, the rear view map lights or the console light. Do you have a GPS, CB, radar detector, aftermarket alarm or radio or audio amplifier/s, check em.
Also, alternators aren't meant to charge up dead batteries, dead batteries draw large current at first and this heats up alternators and shortens their life. Besides, 2 hours of charging won't fully charge up a battery. Buy and use a battery charger and use it at least overnight.
Also, alternators aren't meant to charge up dead batteries, dead batteries draw large current at first and this heats up alternators and shortens their life. Besides, 2 hours of charging won't fully charge up a battery. Buy and use a battery charger and use it at least overnight.
Thread Starter
Burning Brakes
Joined: Jan 2006
Posts: 1,154
Likes: 1
From: St Augustine FL
I will give it a shot. It held a charge overnight and I drove it to work this morning without issue. I may just take the battery and have it tested and buy a new battery and probably a charger too. I did not see any lights on and there are no aftermarket accessories that are installed or used in the car. Thanks again.
Measure the current, GM says it should not exceed 50 milliamps. My 87 draws 27 ma. and I have no problems. Don't leave your key in the ign as this keeps the antitheft circuit on. At night see if you can see the vaniity mirror lights on or the door map lights, the rear view map lights or the console light. Do you have a GPS, CB, radar detector, aftermarket alarm or radio or audio amplifier/s, check em.
Also, alternators aren't meant to charge up dead batteries, dead batteries draw large current at first and this heats up alternators and shortens their life. Besides, 2 hours of charging won't fully charge up a battery. Buy and use a battery charger and use it at least overnight.
Also, alternators aren't meant to charge up dead batteries, dead batteries draw large current at first and this heats up alternators and shortens their life. Besides, 2 hours of charging won't fully charge up a battery. Buy and use a battery charger and use it at least overnight.
Pro
Joined: Feb 2006
Posts: 671
Likes: 10
2021 C4 of the Year - Unmodified Finalist
maybe
My battery in my 87 went dead acouple of times back to back. It turned out to be the under hood light had a faulty mercury switch an was draining the battery.
PS or BS FWIW, don't use your alternator to charge the battery, a charger is much cheaper than an alternator!
PS or BS FWIW, don't use your alternator to charge the battery, a charger is much cheaper than an alternator!
Le Mans Master
Joined: Feb 1999
Posts: 6,470
Likes: 2
From: levittown pa. usa Even a bad day with my `Vette, is better than a good day at work
St. Jude Donor '10
Every Corvette I have ever had would go dead in a couple of weeks of sitting. Now I use a battery tender on both of the ones I have now. 
Instructor
Joined: Aug 2006
Posts: 170
Likes: 0
All good tips but may I add? first I put in a code saver that way nothing has to time out then I put in a knife switch on the neg. side hook up my DMM then open up the switch and read the draw if I want to open the door I close the knife switch so meater does not draw to much amprage also start with 10 amp range just in case as you can see using the switch makes the changes easy IMHO
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
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
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
Tech Contributor
Joined: Oct 2011
Posts: 525
Likes: 9
From: Annapolis MD
