charging problem
Thread Starter
Melting Slicks
Joined: Mar 2005
Posts: 2,187
Likes: 7
From: Chetwynd B.C.
charging problem
I go on a drive for one to two hours and my battery is dead. I had the alternator checked out and it is okay. Where should I start looking now. The car can sit in the garage for days without moving and it will still start up no problem. I think thought the alternator wasn't charging the battery but the alternator is fine (according to the test at the local napa store).
If the alternator is fine but not charging the battery where should I start looking? The battery is only a couple of years old and is a dry cell battery. The regulator was replaced last summer.
What kind of test should I be doing now. If I do a volt test at the battery it reads 12v when motor is not running and doesn't change after the motor is started. It should change to over 13 or 14 once the motor is started shouldn't it? So I would think there is a problem somewhere from the alternator to the battery. What and how should I check for this?
shmoky
If the alternator is fine but not charging the battery where should I start looking? The battery is only a couple of years old and is a dry cell battery. The regulator was replaced last summer.
What kind of test should I be doing now. If I do a volt test at the battery it reads 12v when motor is not running and doesn't change after the motor is started. It should change to over 13 or 14 once the motor is started shouldn't it? So I would think there is a problem somewhere from the alternator to the battery. What and how should I check for this?
shmoky
Safety Car
Joined: Sep 2007
Posts: 4,458
Likes: 331
From: Indy Indiana
check for voltage at the alt output with car running at 2500 RPM and also at Idle, it should be 13+ when the battery is fairly discharged. also, you can do all the tests with the regulator, file the points, check the field voltage and adjust the internal screws, etc.. but regulators are cheap, just replace it and see what happens.. make sure all your connects are good..
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
Take a test light and make sure you have 12v constant at the main (red) terminal on the alternator with the key off. IF not, check the Fusible link at the Starter.
If that's working, check the exciter wire on the connector to the side of the alternator (I believe it is brown). Make sure that has 12v but only with the key on. If not, check the fuses and download a wiring diagram and follow it back.
My guess would be one of the two if your battery is good and the alternator tested fine.
If that's working, check the exciter wire on the connector to the side of the alternator (I believe it is brown). Make sure that has 12v but only with the key on. If not, check the fuses and download a wiring diagram and follow it back.
My guess would be one of the two if your battery is good and the alternator tested fine.
Thread Starter
Melting Slicks
Joined: Mar 2005
Posts: 2,187
Likes: 7
From: Chetwynd B.C.
OKAY I have 12v constant at the main (red)terminal on the Alt. with the key off or on.
The exciter wire (mine is blue) and has 12v only with the key on. Now what?
I've ordered a regulator ($16 canadian) but won't be here til friday.
shmoky
The exciter wire (mine is blue) and has 12v only with the key on. Now what?
I've ordered a regulator ($16 canadian) but won't be here til friday.
shmoky
Le Mans Master
Joined: Feb 2000
Posts: 7,032
Likes: 2
From: Newburgh NY
I'd put a load tester on the battery. It may just be shot.
How many volts are you putting out when running? (When running just use a voltmeter at a 12v source like the Cigarette lighter or fuse box).
While running disconnect the negative battery cable. If it stays running, the alt is doing it's job.
How many volts are you putting out when running? (When running just use a voltmeter at a 12v source like the Cigarette lighter or fuse box).
While running disconnect the negative battery cable. If it stays running, the alt is doing it's job.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
If you run a jumper from the pos term on the back of the alt to the F term on the alt that should put the alt into full output. If that works then the reg could be bad,ungrounded or misadjusted.
You might want to find a manual and check that procedure to be sure,its been awhile since I tested one.
You might want to find a manual and check that procedure to be sure,its been awhile since I tested one.
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Safety Car
Joined: May 2006
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From: Shelton, Connecticut
St. Jude Donor '08-'09-'10-'11-'12-'13-'14-'15-'16
Ground the regulator case
Make sure the regulator case has the ground wire attached to the leg and not isolated with a rubber mount.
Racer
Joined: Oct 2005
Posts: 457
Likes: 1
From: Royal Oak Michigan
Not sure how different your alternator is for your 68 but on my 1980 I had my alternator checked by the local store and they said it was fine. Did all the rootcausing and it still pointed to the alternator. Replaced it yesterday and all is well. Now I have strange engine noise to go after.
Darrel1
Darrel1
Thread Starter
Melting Slicks
Joined: Mar 2005
Posts: 2,187
Likes: 7
From: Chetwynd B.C.
I'd put a load tester on the battery. It may just be shot.
How many volts are you putting out when running? (When running just use a voltmeter at a 12v source like the Cigarette lighter or fuse box).
While running disconnect the negative battery cable. If it stays running, the alt is doing it's job.
How many volts are you putting out when running? (When running just use a voltmeter at a 12v source like the Cigarette lighter or fuse box).
While running disconnect the negative battery cable. If it stays running, the alt is doing it's job.
I checked at the battery and it is just over 12v when not running and NO change when I start it.
Will have to try this but NAPA did a test on the Alt and is is good.
If you run a jumper from the pos term on the back of the alt to the F term on the alt that should put the alt into full output. If that works then the reg could be bad,ungrounded or misadjusted.
You might want to find a manual and check that procedure to be sure,its been awhile since I tested one.
You might want to find a manual and check that procedure to be sure,its been awhile since I tested one.
What next? Any ideas?
shmoky
