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My guess is two part..Sounds as if your alternator is not producing properly but the alternator is not designed to charge the battery from low, just to maintain..Try a good charge on the battery and start there..batteries don't last like they used to
best of luck
chuck
 

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The guys above give very good advice! Also good 'contact cleaners' for your main grounds -are wire brushes or sand paper. You want to see clean bright metal and then coat it with a corrosion inhibitor (honest Vaseline works well and is usually around the house). An electrician friend gave me a bottle of Contax and it may work better but the Vaseline is less messy and easy to find in my garage.

Mark
 

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Discussion Starter #23
This is wonderful advice from you all and I will have another update incoming. Ill address the grounds as you have all kindly suggested. I will also just get a brand new regulator or maybe even look into purchasing a Alternator with a built in regulator. Does anyone know where I can find a the cable that currently leads into the external voltage on the '77 spider ? Is there a specific one I should look for- could not find on center line- or is it pretty generic?

Thanks all :)
 

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An electrician friend gave me a bottle of Contax and it may work better but the Vaseline is less messy
"Less messy" isn't the criteria here. Contax will remove corrosion and make your connections work again. I'm not sure what Vaseline will do.

Alternator with a built in regulator. Does anyone know where I can find a the cable that currently leads into the external voltage on the '77 spider ?
Are you referring to a cable that will connect an internally-regulated alternator to your '77 spider? You don't need a special cable - an internally-regulated alternator uses fewer wires, not more. Just connect the big wire to the 6mm lug on the new alternator (as it was connected to the old alternator), separate the small green wire that goes to the "GEN" light from the old regulator and connect that directly to the "GEN" (or however it's labeled) terminal on the new alternator. That's all there is to it.
 

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"Less messy" isn't the criteria here. Contax will remove corrosion and make your connections work again. I'm not sure what Vaseline will do.
Vaseline is just like dielectric grease but costs much less. It prevents corrosion but will not remove corrosion if it is already present. Maybe that is why I prefer to use a wire brush and or sand paper.

Mark
 

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I'd have the alternator out and over to the auto parts for a test. You may have shorted diodes or just a bad regulator.

Understand this: if the voltage "output" of the alternator is not higher than the charged battery voltage (about 12.4), you are not charging at all - your battery is draining through the alternator, etc. Typically 13.8 VDC is an alternator's output voltage when the regulator is performing perfectly - and I say VDC (Voltage Direct Current) because a bad diode can add AC (Alternating Current). AC won't charge your battery, and over time can damage it.

At an alternator test station, they often show a picture of the output waveform, and bad diodes show as pulses of distorted or even reversed voltage (it's never too smooth, but a good one is repetitive, without differences)
 

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Discussion Starter #29
@Alfajay I mean the wires that currently lead from my alternator to my voltage regulator (attached photo).

I am going to get my alternator and regulator tested and will be back with the results. If they are on their way out the door than I guess I might shell out the substantial money for a refurbished one with a internal regulator.
@bruce1976spider that was extremely helpful! I need to learn just how exactly this system is supposed to be functioning to help myself understand what exactly is wrong with my alfa. I appreciate the feed back.

Thank you all for your responses and I will keep you updated. My days off are usually Tuesdays and Wensdays and thats when I usually get time to work on her. I actually got my first sunburn of the year working on her last time hahaha ! I will include more photos in the next update.

Thanks :)
 

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@Alfajay I mean the wires that currently lead from my alternator to my voltage regulator (attached photo).
Matteo:

No photo was attached. But I can picture what you mean: a three-wire connection, with two three-terminal plugs on either end. No one sells that. Perhaps someone here will have one used. Or you could make one, using female terminals with a tang to grip the connector. What happened to your old wiring?

I am going to get my alternator and regulator tested and will be back with the results. If they are on their way out the door than I guess I might shell out the substantial money for a refurbished one with a internal regulator.
New internally-regulated alternators shouldn't cost any more than a new copy of your old alternator. In fact, buying a new regulator + a new externally-regulated alternator would probably cost more than a new internally-regulated alternator. Here's one source:

90-94 Alfa Romeo Spider Alternator High Output 80 Amp Generator | eBay

But the least expensive solution is probably going to be rebuilding the alternator that you have. If the shop can rebuild it, and verify that your regulator is OK, you should get away for ~ $100.
 
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