still have voltage drops

[hippymill]

posted a few days ago about my dying alternator. replaced it with a 94a from advance auto, but am still getting voltage drops when at idle with the lights on. won't do it after its warmed up either. just whem the motor's cold, and i come to a stopsign. then the voltage drops down to 8-9 volts on the gauge, and the lights dim considerably, so i know its an actual drop, not just the gauge. any thoughts?

[Joe Guilbeau]

The engine warming up or not should have nothing to do with the symtoms that you are experiencing.

Either the magnetic field of the Rotor is inducing an EMF in the Stator windings or it isn't.

You need to get a voltmeter and go under the hood and measure the voltage on the battery in the morning. It should read at 12.75Vdc or so, that means that the battery is fully charged.

If it reads less than that, it means that the battery no longer has a full charge on it.

Possible reasons:

Alternator is not charging the battery

Alternator is charging the battery, but there is a parisitic draw that depletes the battery charge.

Alternator is charging the battery, but cannot keep up with the load on the battery.

When the alternator is charging, you should see something like 13.85Vdc to 14.8Vdc across the batttery with a voltmeter. Revving the engine should enable the rotor magnetic field and allow the alternator to supply a charging voltage to the battery.

You may have to rev the engine to 2000-3000 RPMs for this to happen. Depends on the regulator in the alternator.

Let us know what the above tests reveal.

[hippymill]

will check tonight when i get home. thnaks

[Quiet Rebel]

Simple-minded idea, but could the belt be a touch too loose, and the heated engine makes the rubber softer and stickier?