Electrical connection between Battery, Alternator and Starter

petex19

petex19

True Classic
It's winter project time and I want to fix my low voltage issues so I decided to replace the heavy gauge wires going from the battery to the solenoid/starter and the one from the solenoid/starter to the alternator.

When I removed them I was absolutely shocked :eek: and pleased at the same time because I believe I've found my voltage issues problem. Each of the two 4 gauge wires had one spot that the red coating was completely gone and the wire was half gone and corroded. Over the years these wires must have made contact with something and melted the sleeve off. It's amazing that any voltage passed through them at all.

I took photos of them but my photo software is currently not working but I will post photos later.

My question to all is: Am I connecting the starter/solenoid and alternator correctly?

My cars runs amazing but I just came from a local auto parts store to buy the 4 gauge wires and I told him what I was doing and he did one of these :wacko: He states that he has never heard of the alternator connecting to the solenoid and he only knows of the alternator using like a 10 gauge wire, not a 4 gauge one. He states that the alternator should connect to the electrical of the car.

My setup if it's correct:

Positive battery terminal to the solenoid, solenoid(connected to the same bolt) to the alternator (Magnetti Marelli) main bolt.

Negative battery terminal to chassis ground.

If it matters, my battery is located in the rear trunk so everything is relatively close together.

'PeteX1/9
 
Pete, he's right about the 10Ga wire

The alternator doesn't need a 4 Ga wire on the X1/9. You can use one if you want,
but it's WAY overkill. The 10Ga will feed 40 Amps DC back to the battery all day long.
Not a bad charge when you think about it.

That mechanic you mention doesn't know about X1/9's, otherwise he'd understand that they ran this wire to the
starter cable at one time to pump the generated current back to the battery. With using the 4Ga line that feeds back to the battery
to (basically) charge it, you're getting the best conductor all the way back, (to the battery) so doing this is perfectly fine.

The "proper" way in the late model harnesses was to run the line back to the fuse box, where all
the 10Ga wires run together. One of which comes directly from the battery. Theoretically (and in reality) not as good as using
the 4Ga wire at the starter, as was from the beginning.
 
Thanks alot Bob, I know I can take your word to the bank anything electrical :headbang:

I feel much better now, nothing worse then second guessing yourself and wondering if the 'chevy' guy at the autoparts store ( the same guy that when I said Fiat responded "who makes that") may actually be right.

'PeteX1/9
 
Fool me once... shame on him!

Fool me twice... I believe its YOUR turn to be shamed!

Well, at least the counter guy this time said he never HEARD of it before... not that it "Can't be done" kinda thing. I'll give him that much credit.

Always learnin', 'less yur dead!
 
PATH

Pete, what path did the green wire take? Did it go straight back? I have a short and this is probably my problem.:wall:
 
What green wire ? The only wires ran were positive + red in my case 4 gauge wires between battery, solenoid and alternator and a black - negative to chassis ground.

Not sure which wire you are asking about ?

'PeteX1/9
 
Green wire?

petex19 said:
What green wire ? The only wires ran were positive + red in my case 4 gauge wires between battery, solenoid and alternator and a black - negative to chassis ground.
Click to expand...

In an early OEM wiring harness, the very heavy wire from battery + terminal to solenoid is green. Sounds like you have a red one instead...
 
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