I have a brand new alternator, and ever since I put it in, it has not charged the battery. I have to constantly be recharging the battery. What would cause this? May this have something to do with rear battery mount?
Alternator not charging battery
- Thread starter str8stang036
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Zero_chance
Founding Member
Did your last alternator die or did you upgrade? Are you certain you dont have a parasitic draw thats sucking down the battery? If you have a DVOM check voltage at the battery with the car off and then check it with the car on. Should be around 12.6 with car off and around 14.4 give or take with the car on. If the alt wasnt charging the car would die while driving around town once the accesories sucked the battery down. If that doesnt happen then you likely have a draw in the system.
get a voltmeter (can be had for as little as 4 bux) and put the positive lead on the alternator post and the negative lead on a ground and see what the voltage is. It should be around 13.6 - 14.6 or so. If there is about that much voltage there then your alt is good. Do a check at the battery next with the car running and see what the voltage is....it should be almost the same as what your last reading was. If you are getting spec voltage at the battery then it's time for a new battery. If not then chances are it's the fusible link coming off the alternator power wire.
if the alternator did not put out the spec. voltage...then either your alternator's bad or something's screwed up in the wiring.
post up and let us know.
if the alternator did not put out the spec. voltage...then either your alternator's bad or something's screwed up in the wiring.
post up and let us know.
And ensure all of your connections are free of corrosion. Even if it means disconnecting and cleaning them up. I've been fighting a charging system problem myself, even with the entire system having been rewired. Once it warms up, I'll be going through the entire system again because it's a PITA to not have the car start once you turn it off. My brand new alternator is putting out sufficient power to run the car, but for whatever reason, doesn't charge the battery, so I know how you feel 100%.
The alternator is my first one on the car. When I finish charging the battery the charge is around 14 volts. I can see it because I have an autometer gauge I can look at. Once the car gets started the power slowly goes down almost to about 10 volts. I'm starting to think I have a power drain like some of you have suggested. I have to check the voltages as suggested and maybe ill even take ithe alternator to make sure its not that.
Based on your description, I would honestly suspect a bad diode or two in the alternator. It's charging, but not giving its full rated output, so the demand is exceeding the delivery from the alternator. Have a store bench test the alternator to see if they can view it's full output.
95strokerPSU
Member
Check your grounds. I had a similair no charge issue because I had the alternator bracket powdercoated which did not allow the alternator to ground to the engine block.
5.0_GT_kid
Dirt-Old 20+Year Member
I agree with this. Awhile back I was having a similar problem and it turned out the alternator was dying, but it was still putting out enough to keep the car running. Once I shut the car off though, I was ****ed.
blksn955.o
Founding Member
Check your grounds, the block to chassis is a biggie also check the batt. to block.
I had something sim. when my grounds went to crap...it got to the point it would not start but started by slowly not charging as heat built up into the area.
Good point made about powdercoat and painting above. I also had my brackets/alt housing powdercoated and you have to clean the contacts were the alt. mounts to the brackets. The alt. grounds threw the brackets so also check the bolts that bolt the bracket to the block as well.
Also check the alt. wires and make sure they are good...the main power wire has an fuse and the connections could be grungy/frayed.
Is the batt. ok? The batt. itself could not be holding a charge under load for very long due to a bad cell or something.
I had something sim. when my grounds went to crap...it got to the point it would not start but started by slowly not charging as heat built up into the area.
Good point made about powdercoat and painting above. I also had my brackets/alt housing powdercoated and you have to clean the contacts were the alt. mounts to the brackets. The alt. grounds threw the brackets so also check the bolts that bolt the bracket to the block as well.
Also check the alt. wires and make sure they are good...the main power wire has an fuse and the connections could be grungy/frayed.
Is the batt. ok? The batt. itself could not be holding a charge under load for very long due to a bad cell or something.
mo_dingo
Dirt-Old 20+Year Member
the easiest thing to do is put an amp clamp on the thick alternator cable. If you see zero amps, you have a problem with the alternator in some fashion. Forget the rest of the system and focus on it. Many alternators are dead right out of the box. Once the alternator has been eliminated from the equation, then test other sections. Isolate and divide!!!
I am going to check my alternator today. You guys make a point about the engine ground and the brackets. I don't have stock brackets, I have the March bracket assemblies for alternator and power steering.
I also painted the backside of the alternator black.
I also painted the backside of the alternator black.
Well the verdict is in. My alternator is bad. Hopefully that is the only problem for charging the battery. Battery tested good.
The mystery continues. I went to exchange my alternator for a new. When they tested it, it tested OK!. It was tested 3 times and every single time it was OK. Weird thing is yesterday I got it tested at autozone,and their computer kept coming up with an error.
Need some help guys!! How exactly is your alternator connected. Describe the wires to and from yours to make sure it matches mine.
Right now it has both stock plugs connected to the alternator, and the nut on the alternator is connected to a wire that goes to the fuse box positve side terminal. Is that right?
Need some help guys!! How exactly is your alternator connected. Describe the wires to and from yours to make sure it matches mine.
Right now it has both stock plugs connected to the alternator, and the nut on the alternator is connected to a wire that goes to the fuse box positve side terminal. Is that right?
Take the alt elsewhere for another test. I'd need to see several good tests from different people before dismissing a bad test. I've had the stores disagree before and the one that said it was bad was often correct in the end.
On the regulator, the terminals are labeled ASI. A is battery current. I is from the ignition. S is the stator circuit.
Your power cable is connected to the correct spot on the PDC. Ensure the fusible links are intact on the power cable.
Ensure the alt fuse is intact (it's in the underhood fusebox).
Good luck.
On the regulator, the terminals are labeled ASI. A is battery current. I is from the ignition. S is the stator circuit.
Your power cable is connected to the correct spot on the PDC. Ensure the fusible links are intact on the power cable.
Ensure the alt fuse is intact (it's in the underhood fusebox).
Good luck.
Bosko5.0
Active Member
Well I went to advance auto parts to get it rechecked, and it passed the test.
Where are the fusible links your talking about Hissin?
Where are the fusible links your talking about Hissin?
i am still curently having this problem... ive replaced my batery as stated. when i turn on my acessories (lights and vent fan) my battery meter continually drops down till about ten volts then it will hold there at idle. if i give it a little gas the gage will go back up to normal. i let off it goes back down.... this is a sign that my alternator works right??? idk what to do i guess i will trace the ground and see if it is loose or damaged somewhere... what else could it be?
Bosko5.0
Active Member
jomull55- either you are running underdrive pullies or your alternator is going bad. you should take your car to a discoutn auto or autozone and have them test it while its running.
The fusible link is in the cable that runs from the fuse box stud to the alternator. two wires into one, it doesn't really look likea fuse.
The fusible link is in the cable that runs from the fuse box stud to the alternator. two wires into one, it doesn't really look likea fuse.
