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Alternator Not Charging


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Hi guys,



Basically I thought it would be a nice idea to refresh my alternator bearings, and fit an ally pulley, which didn't fit, at the same time.



However upon installation I find that it no longer wants to charge. It was charging fine before hand.



There are a few caveats to this.



When I was rebuilding the alternator, a mate of mine knocked over a tray full of bits. When I reinstalled the alternator, I omitted the plastic cup that sits on the threaded power out.



This caused a lovely spark and started chewing up the terminals on the battery.



Realising the error of my ways, I removed the alternator, refitted the cup then reinstalled it.



Alas this is has not solved my problem.



I figured I may have damaged the internals of the alternator, so I've replaced all the internals, except the bushes.



I've just fired it up again and still not charging.



The belt feels rather tight, although a nasty oil leak has developed and is kinda on the belt, but I can see the alternator spinning.



I've checked the wire from the power to the fuse for continuity and I've also checked the fuse. All seems to be fine.



The only thing I haven't yet tested is the plug wire for the alternator.



When I had the alternator on th bench, I wanted to see if it was generating any current:



https://youtu.be/e4_JnyW25Rs



This is Micro Amps but it definitely seems to be responding.



Is there something else I need to check to get this fixed?



Thanks




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  • 2 weeks later...

I've just watched your video. You won't get any voltage out of an alternator that way. It needs a 12v power supply to energise the rotor (create magnetic feild) there will be a main live from the alt to the fuse box, where it goes into the fuse box it'll have a main fuse @ 60/80/100amp have you checked them plus the small energise wire will be fused. You need to have input to have an output.

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Yes Luke I'm aware of how the alternator works, and I'm not saying that as a dick, cause before this little experiment I didn't have a clue.



However, it's possible for the core to have residual magnetism. And there s no way this is coincidence that it was generating current whilst spinning it. But you're right to say that it doesn't test the electronics, which could have been at fault, although everything has been replaced.



EP82GTfusebox.jpg



So ALT and AM1 are fine



I haven't seen a 100 Amp fuse, where do I find that?



I think you are right Luke, I can't see what else it can be. It was the first thing you said, but I checked all the above fuses. The two circular things are relays, and the boxes above them are relays.



So where is this 100Amp fuse?



You will be my best bud forever and ever if this is what fixes it as I am royally annoyed with myself I haven't been able to fix it.



Thank you for replying


Edited by Calum122
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I said 60/80/100amp as in it could be one of three sizes. Yours is 80amp so it's the 80amp one that will be the main live to the alt.

If the battery light is going out it would suggest that the alt is charging. The way it works is fused live from fusebox to bulb on dash then from the other side of the Bulb to alt small post which is earth. The alt small post is only earth when not charging. When the alt starts to charge the small post goes live which turns the light out.

Just realised starlet have a plug not a small post. So one of the wires in the plug will be the battery bulb wire.

And you won't get voltage over a fuse, both legs of a fuse are connected together so technically your just checking a short. You need to put one multimeter lead to earth and check both side of the fuse with the other lead. When checked and both side of the fuse you get the same reading on the multimeter you know that the fuse is ok if one side is showing a reading and the other shows nothing it is blown.

Edited by lukEp
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Yeah I noticed that from the wiring diagram.

So basically still no closer to solving this. It's clearly not charging with only 11 volts at the battery, drops if you apply load.

My hope is that I am not earthing the battery properly. I am in the process of relocating the battery to the boot. I will get an earthing kit and make sure it's not that.

Otherwise I am at a loss.

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If the car starts then the alternator has a good earth as the starter and alternator share the same earth and live.

Have you checked the fuses in the car?

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In car cabin fuses all okay. And can't find a fault with any of the other fuses, unless of course I have missed a fuse under the dash that I am not aware of.

I have checked continuity from the alternator to the fuse box. That's find. The wire is not broken.

However I am still not measuring any power st the fuse box. My multimeter says zero volts, even when the engine is running.

Edited by Calum122
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[quote name="lukEp" post="1207701" timestamp="1488652699"

Just realised starlet have a plug not a small post. So one of the wires in the plug will be the battery bulb wire.

And you won't get voltage over a fuse, both legs of a fuse are connected together so technically your just checking a short. You need to put one multimeter lead to earth and check both side of the fuse with the other lead. When checked and both side of the fuse you get the same reading on the multimeter you know that the fuse is ok if one side is showing a reading and the other shows nothing it is blown.

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Why I asked if the battery light comes on as linked to the alternator charging. An old volvo I had the alternator was 'jump started' by revving over 4000.found this out after an issue with the 12v. Wonder if it's worth a go?

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  • 1 year later...
On 04/03/2017, 21:10:54, Ollieh17 said:

Why I asked if the battery light comes on as linked to the alternator charging. An old volvo I had the alternator was 'jump started' by revving over 4000.found this out after an issue with the 12v. Wonder if it's worth a go?

Lol, I'm so quick at fixing stuff it's unreal.

 

Ollie, you were spot on mate. After 15 months, I've actually driven the car up the road, and low and behold when I got back I was getting 14V at the battery on idle.


So you were spot on mate.

 

The car has been sat for three years, after priming the engine with the fuel pump off. A few turns with the ignition on and off. I kid you not, car started in an instant. Didn't even add any fresh fuel. Just a quick oil change.

 

Car sounded very health too, didn't smell great, but sounded good.

 

Very well designed.

 

But yeah, okay, so new Alternator fixed the problem. Happy Days.

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