Alternator charging question

[Fern]

My volt gauge has been reading 15 volts. I checked all the grounds and voltage regulator and all is good.
Put a multimeter to battery and good at 12.6, started car and multimeter went up to 15 volts.
Does this mean alternator is no good and overcharging the battery?
By the way new wiring harness done original, haven't done bypass and amp gauge still working.

[dodj]

Start with cleaning all the connections. B/H, Starter relay, ammeter

[Bullitt-]

 Check voltage on the blue wire at the voltage regulator, it should be very close to battery voltage. If not a poor connection is causing the voltage regulator to think the battery is low and turns the alternator up.

[Rich G.]

Voltage regulator controls how much the alternator puts out.

[GoodysGotaCuda]

Check voltage on the blue wire at the voltage regulator, it should be very close to battery voltage. If not a poor connection is causing the voltage regulator to think the battery is low and turns the alternator up.

This, start here.

With the key on you should be able to take one lead of your voltmeter to the blue wire on the VR and the other to your B+.

This is performing a voltage drop test, which should be quite low, <0.5v.

If it's higher than that, then your VR is thinking your battery is lower than it actually is and demanding more voltage out of the alternator....leading to overcharging.

[Fern]

Check voltage on the blue wire at the voltage regulator, it should be very close to battery voltage. If not a poor connection is causing the voltage regulator to think the battery is low and turns the alternator up.

This, start here.

With the key on you should be able to take one lead of your voltmeter to the blue wire on the VR and the other to your B+.

This is performing a voltage drop test, which should be quite low, <0.5v.

If it's higher than that, then your VR is thinking your battery is lower than it actually is and demanding more voltage out of the alternator....leading to overcharging.

Great, I will try that this weekend.
By the way, I had tested the voltage at the ballast resister and it read 14.2. If that means anything?

[GoodysGotaCuda]

Check voltage on the blue wire at the voltage regulator, it should be very close to battery voltage. If not a poor connection is causing the voltage regulator to think the battery is low and turns the alternator up.

This, start here.

With the key on you should be able to take one lead of your voltmeter to the blue wire on the VR and the other to your B+.

This is performing a voltage drop test, which should be quite low, <0.5v.

If it's higher than that, then your VR is thinking your battery is lower than it actually is and demanding more voltage out of the alternator....leading to overcharging.

Great, I will try that this weekend.
By the way, I had tested the voltage at the ballast resister and it read 14.2. If that means anything?

I don't recall if that wire also feeds the VR, but I don't think so.

You must know what the battery voltage is when taking the reading, otherwise it's just a number. This is why I prefer the voltage drop method.


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[Fern]

Ok, so I put the voltage reader from B+ to blue wire at voltage regulator and got a drop of 0.78.
The electrical  choke is also tied into the back of alternator at the same point. Disconnected the choke wire answer dropped to .69. Started car and volt meter inside car read 15, disconnected choke while running and still at 15.

[Bullitt-]

At this point I would trace that blue wire back checking where the voltage drop starts, there's probably a corroded connector or the wire has broken down.