Altenator good but still not charging

widomkr79

Daily Driver
Aug 10, 2010
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I have a 140 amp altenator running my car and ever since I put the motor back in I am not getting it to charge my battery. It is a 3 wire set up. First I wasn't sensing any voltage from the brown wire on the plug so I I ran a separate wire with a resistor to the fuse panel but now when the car is running I am showing 14.7 volts at the brown/exciter wire but not at the bat pole on the altenator.

Any ideas I am losing my mind with this ordeal?
 

Ed Cannon

Pro Stocker
Jul 17, 2009
1,682
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Johnson City Tn
Make sure you have B+ @ the big wire on the back and on the big wire at the regulator. Make sure your alt is grounded good. Also make sure the belt is tight. If all that checks out have the alt bench tested.
 

widomkr79

Daily Driver
Thread starter
Aug 10, 2010
25
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0
I have it hooked as u say with the bat+ and the big red wire. I only have a 12gage wire on both of those though. Not sure if that would cause the 14 volts not to transfer to he battery? Also, what the best way to check the altenator to insure its getting pepper ground? Well I'm going to to run a 4 guage battery wire to the alt tomorrow.
 

Ed Cannon

Pro Stocker
Jul 17, 2009
1,682
0
0
Johnson City Tn
About the ground, just be sure the alternator mounting is clean and tight. Checking it for a voltage drop is the best way. You may have the wires reversed on the regulator pin # 2 should have B+ on it # 1 is the bulb or exciter circuit. Make sure to use a fuse link on the charge wire. about that image don't use an ammeter, ammeter = fire.
 

widomkr79

Daily Driver
Thread starter
Aug 10, 2010
25
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Appreciate all the insight but had the same wiring and altenator before I pulled the motor and that's what's driving me crazy. I do have a chasis ground for the battery but none off the motor itself. Went and picked up a new ground strap for the head to the firewall and going to increase the guage for the bat alt. to the battery.. I am hoping that does it cause I am vomiting with every look at diagrams. I've tried everything and can't think of anything else so that means its something stupid like a ground or power supply. If so will explain no power when getting on it since I put the new motor due to no good feed of volts to my devices.
 

widomkr79

Daily Driver
Thread starter
Aug 10, 2010
25
0
0
Added a ground strap from head to firewall and cleaned up the battery ground to chasis. Also added a 4guage wire from bat post on alt to battery and whaaalhaaaa!!!! All this frustration over a ground...

THANKS ED, APPRECIATE YOUR TIME AND INSIGHT
 

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