Dead Battery Diagnosis
Thread Starter
Instructor
Joined: Dec 2005
Posts: 103
Likes: 0
From: Pittsburgh PA
Dead Battery Diagnosis
I went to start the car to head for a cruise on this beautiful day and there was nothing when I turned the key. My 15 YO daughter was not happy since she has been wanting a ride!
The car is a 71 big block. The last time I drove it was 3-4 weeks ago.
The clock was not running, no interior lights, etc, so I am pretty sure it is electrical. I put my battery tender on it and not the clock is running, interior lights work, ... The alternator belt appears tight. The battery looks pretty new, I'll have to look through the receipts I got last fall when I bought the car.
I am a new Vette owner, and learning maintenance and repair as I go. Once I get it started, I was wondering what to check for. I realize the battery tender will take a day or two to charge.
1. Voltage from the alternator when running, I think it should be greater than 13 volts. Is that correct?
2. Is there any way I can check the battery for a bad cell? Can I use a volt/ohm meter to check for a short?
3. I was a bit leery of jumping the car with the battery inside. Are there any real problems with jumping an old Vette?
Thanks,
Rich
The car is a 71 big block. The last time I drove it was 3-4 weeks ago.
The clock was not running, no interior lights, etc, so I am pretty sure it is electrical. I put my battery tender on it and not the clock is running, interior lights work, ... The alternator belt appears tight. The battery looks pretty new, I'll have to look through the receipts I got last fall when I bought the car.
I am a new Vette owner, and learning maintenance and repair as I go. Once I get it started, I was wondering what to check for. I realize the battery tender will take a day or two to charge.
1. Voltage from the alternator when running, I think it should be greater than 13 volts. Is that correct?
2. Is there any way I can check the battery for a bad cell? Can I use a volt/ohm meter to check for a short?
3. I was a bit leery of jumping the car with the battery inside. Are there any real problems with jumping an old Vette?
Thanks,
Rich
Last edited by Rich_71Vette; May 28, 2006 at 03:23 PM.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
#1 yes, 13.7 or so when running
#2 charge the battery and check for leakage current with everything turned off, disconnect pos post, set meter for measuring amps and put it in line with the battery cable and battery, should not be more than a few miliamps, if more, there is a problem, pull fuses til you find it.
#3 Jumping the car is not a problem, use the same caution as with any other car.
tracing down errant current draw can be a pita. set up like #2, pull fuses til it goes away, if it doesn't disconect alt, still there? Light timer, etc...
#2 charge the battery and check for leakage current with everything turned off, disconnect pos post, set meter for measuring amps and put it in line with the battery cable and battery, should not be more than a few miliamps, if more, there is a problem, pull fuses til you find it.
#3 Jumping the car is not a problem, use the same caution as with any other car.
tracing down errant current draw can be a pita. set up like #2, pull fuses til it goes away, if it doesn't disconect alt, still there? Light timer, etc...
Race Director
Joined: Sep 2005
Posts: 18,640
Likes: 121
From: Farragut,TN
Since it's a 71 don't think there should be a battery drain with the ignition switch off. I would suppect the battery or connections. Had the same problem with a '83 mustang 5.0. after sitting for a while all that would happen is you would hear the relay click. pulled the cables off battery positive cable was burnt black on the battery connection due to loose connection. Had the same problem with the 69 corvette turned out to be the battery connections.
