71 Battery drain...
Thread Starter
Instructor
Joined: Oct 2005
Posts: 237
Likes: 0
From: San Jose area CA
71 Battery drain...
The 71 seems to be draining the battery... it will start ok for a number of weeks then the battery is too weak to crank the engine. Just put a new battery in at the beginning of the year. I know if the wiper override switch is on, there is a constant drain, but it is OFF.
Other than the clock, what else has a constant drain on the battery? How can I check for a drain?
Thanks,
Other than the clock, what else has a constant drain on the battery? How can I check for a drain?
Thanks,
Melting Slicks
Joined: Dec 2004
Posts: 2,101
Likes: 3
From: Cruising somewhere in St. Louis, Missouri
my 71 had a starter solenoid that was draining the battery and having intermittent starts (it was shorting out). So i replaced it and everything is perfect.
Jim
Jim
Burning Brakes
Joined: Jun 2005
Posts: 769
Likes: 0
From: NorCal 71 Lt-1
67VetteMan,
you need to check for parasitic drain with a dvom (digital volt ohm meter) that can read in milliamps. setup the meter so that your reading it in amps (milliamp scale) then disconnect the negative battery cable and install the meter leads in series, one on the negative battery cable and the other on the negative battery terminal post then read the meter. i'm not sure what the exact draw would be but a new car with all the bells and whistles is around 25-35 milliamps. if you only have a clock then you should not have much draw. if it's excessive, you will need to start removing fuses and or individual components to locate the source of the draw. good luck!
you need to check for parasitic drain with a dvom (digital volt ohm meter) that can read in milliamps. setup the meter so that your reading it in amps (milliamp scale) then disconnect the negative battery cable and install the meter leads in series, one on the negative battery cable and the other on the negative battery terminal post then read the meter. i'm not sure what the exact draw would be but a new car with all the bells and whistles is around 25-35 milliamps. if you only have a clock then you should not have much draw. if it's excessive, you will need to start removing fuses and or individual components to locate the source of the draw. good luck!
Team Owner
Joined: Oct 2004
Posts: 23,831
Likes: 10
From: Springfield MO
St. Jude Donor '07
I've said it every time this has come up...but my 77 had a short in the starter coils. I never did figure out what the problem was, until I got so frustrated with the flaky starter that I ripped it out and replaced it with a BB502 starter. Lo and behold, my parasitic drain was gone. I know it wasn't the solenoid, because I had changed it.
Racer
Joined: Dec 2003
Posts: 275
Likes: 6
From: NY
With your DVM set to read current, the meters internal fuse is now in play. Meters typically max out at 2A. If you happen to hit the brake pedal while swapping fuses the current drawn will take out your meter's fuse. Just a thought . [Been there , done that]
Burning Brakes
Joined: Sep 2004
Posts: 1,167
Likes: 2
From: Ft.Worth Texas
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