Battery drain problem
Thread Starter
Burning Brakes
Joined: Nov 2010
Posts: 1,233
Likes: 113
From: Oakland, Maine
Battery drain problem
First a confession, this is on my 56 Chevy convertible, all of the Corvettes are fine. I have dealt with the problem by using a Ron Francis remote battery shut off but now I want to find the source of the drain. I have disconnected my battery ground (negative) cable and used a test light between the cable and the post, getting a faint glow which measures 8.19 ohms when I use a meter. I have unplugged the clock, removed fuses one at a time, and disconnected the generator. Doors are closed and I get a much greater draw when I open a door. I have not yet tried the horn relay or the brake light switch but I am running out of ideas. Any thoughts? Bill
Burning Brakes
Joined: Aug 2011
Posts: 878
Likes: 2
Make sure the battery has a full charge.
Disconnect the battery’s ground cable and wire your ammeter in series between the battery terminal and the cable.
Take a reading. Then start disconnecting loads one at a time. Make sure you include relays. They are notorious for sticking slightly and draining batteries.
Disconnect the battery’s ground cable and wire your ammeter in series between the battery terminal and the cable.
Take a reading. Then start disconnecting loads one at a time. Make sure you include relays. They are notorious for sticking slightly and draining batteries.
Race Director
Joined: Apr 2005
Posts: 11,265
Likes: 2,131
From: Bowling Green, Kentucky
First a confession, this is on my 56 Chevy convertible, all of the Corvettes are fine. I have dealt with the problem by using a Ron Francis remote battery shut off but now I want to find the source of the drain. I have disconnected my battery ground (negative) cable and used a test light between the cable and the post, getting a faint glow which measures 8.19 ohms when I use a meter. I have unplugged the clock, removed fuses one at a time, and disconnected the generator. Doors are closed and I get a much greater draw when I open a door. I have not yet tried the horn relay or the brake light switch but I am running out of ideas. Any thoughts? Bill
Larry
Le Mans Master
Joined: Nov 2009
Posts: 5,442
Likes: 64
From: 50 kilometers outside Oslo Norway
I have a kill switch on my car. No way that the battery can be drained
It also helps if somebody tries to steal your car if you hide the kill switch under the dash or somewhere
It also helps if somebody tries to steal your car if you hide the kill switch under the dash or somewhere
Melting Slicks
Joined: Feb 2007
Posts: 2,937
Likes: 163
From: OP Kansas
C2 of Year Finalist (appearance mods) 2019
He has a Ron Francis remote battery shut off. He wants to find the problem instead of work around it.
I also would disconnect the Alternator to rule that out. Sometimes the diodes go bad and will drain your battery overnight.
I also would disconnect the Alternator to rule that out. Sometimes the diodes go bad and will drain your battery overnight.
Thread Starter
Burning Brakes
Joined: Nov 2010
Posts: 1,233
Likes: 113
From: Oakland, Maine
I indeed have avoided the problem by using my remote kill switch which shuts off power but I want to find the culprit. I have a generator, not alternator. I understand using a meter to see when ohms drop off but there has been no drop with anything that I have tried. Clearly it is not a fused circuit as removing fuses still left a draw. I am running out of things to chase. Could a horn relay cause this? Car has overdrive but that kickdown switch is not live all of the time. Horn relay, brake light switch and doors are all that I can think of as possible sources that I have not chased down.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
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
Thread Starter
Burning Brakes
Joined: Nov 2010
Posts: 1,233
Likes: 113
From: Oakland, Maine
Thread Starter
Burning Brakes
Joined: Nov 2010
Posts: 1,233
Likes: 113
From: Oakland, Maine
I should have said the courtesy light that goes on when the doors open, just like in my 62 and 54 Corvette. The switch seems to shut off the light so I felt that this could not be the problem. After lunch I will remove power to the various relays.
Burning Brakes
Joined: Aug 2011
Posts: 878
Likes: 2
You're not looking for ohms and resistance. Your looking for amperage drain. If you hook your meter up like i described and set it for amps you should be able to isolate the drain. Start your meter on a higher amperage setting and bring it down one setting at a time so you don't blow the fuse in the meter.
Le Mans Master
Joined: Feb 2008
Posts: 5,214
Likes: 447
From: NJ Hockey beer league
AMP meter is the best way to find the problem (good advise as stated by Lonestar). One other quick thing, is the Cigarette lighter. Remove the element (or anything plugged in there) and see if there is any change. 
Pilot Dan
Pilot Dan
Thread Starter
Burning Brakes
Joined: Nov 2010
Posts: 1,233
Likes: 113
From: Oakland, Maine
I have just removed wires for relays to overdrive and horn as well as removed the lighter element. I still get a faint glow in my test light. All that I have left are door switches and brake switch which I will do tomorrow.
I have used a test light between negative post and negative cable. Is this just as good as with the positive side like some troubleshooting books suggest? Because the test light is barely glowing I assume that I have a very minor draw. My multimeter does not test for amps-any suggestions for a good and cheap meter that has this function? If tomorrow does not bring any solution I plan to shut off the kill switch, pull up the car cover and deal with other things that are less problematic. Life is too short to try and make everything function the way they should.
I have used a test light between negative post and negative cable. Is this just as good as with the positive side like some troubleshooting books suggest? Because the test light is barely glowing I assume that I have a very minor draw. My multimeter does not test for amps-any suggestions for a good and cheap meter that has this function? If tomorrow does not bring any solution I plan to shut off the kill switch, pull up the car cover and deal with other things that are less problematic. Life is too short to try and make everything function the way they should.
Race Director
Joined: Apr 2005
Posts: 11,265
Likes: 2,131
From: Bowling Green, Kentucky
I have just removed wires for relays to overdrive and horn as well as removed the lighter element. I still get a faint glow in my test light. All that I have left are door switches and brake switch which I will do tomorrow.
I have used a test light between negative post and negative cable. Is this just as good as with the positive side like some troubleshooting books suggest? Because the test light is barely glowing I assume that I have a very minor draw. My multimeter does not test for amps-any suggestions for a good and cheap meter that has this function? If tomorrow does not bring any solution I plan to shut off the kill switch, pull up the car cover and deal with other things that are less problematic. Life is too short to try and make everything function the way they should.
I have used a test light between negative post and negative cable. Is this just as good as with the positive side like some troubleshooting books suggest? Because the test light is barely glowing I assume that I have a very minor draw. My multimeter does not test for amps-any suggestions for a good and cheap meter that has this function? If tomorrow does not bring any solution I plan to shut off the kill switch, pull up the car cover and deal with other things that are less problematic. Life is too short to try and make everything function the way they should.
My recommendation is to get a good Fluke meter. I have a #73-3. The best one around is an #87-3 or 87-5. There are many in between. Just check the Fluke website, and then look for the best deal on Ebay or other web/internet stores. Probably $ 200-300.
This tool is to valuable and important to go cheap.
Others may have a different perspective and recommend other brands/models.
Larry
Thread Starter
Burning Brakes
Joined: Nov 2010
Posts: 1,233
Likes: 113
From: Oakland, Maine
Burning Brakes
Joined: Aug 2011
Posts: 878
Likes: 2
Huh? Why are you still trying to easter egg hunt this problem? If you buy a fluke meter as stated per a previous reply and hook it up as i suggested and methodically disconnect loads to your electrical system you will isolate your problem.