Alternator Scamp /6

"It depends."

If you have a larger output alternator that has been installed on the car, and who knows after that many years?

So let's say that the battery is down a little........................

been sitting a week, or maybe the battery is a few years old, and isn't "what it should be," or maybe you have a stereo/ other device with "keep alive" memory, or some other minor draw. OR maybe you just cranked the starter quite a bit to start the car................

so the battery is down....................

Now the thing will charge at a high rate until the battery starts to come up, and then the ammeter should gradually drop to "average" around center

HERE IS how an ammeter should work:

Everything off, centered. This means ZERO current being charged into or drawn out of the battery.

Get in the car, turn on key or lights, or any other load. Ammeter should deflect by some amount, depending on the amount of current.

Start the car-----------depending on how long you cranked the starter, and how large the alternator is, it should charge by some amount. In winter, turning on lights, heater, will REDUCE this amount of charge.

At some point, as the battery "comes back up," the charge rate should drop off and the ammeter should run down the road at just about any speed near zero.

Stopped in traffic, slow idle, in gear, heater, lights on, ammeter MAY discharge some amount, showing alternator will not put out at that slow RPM. "A little throttle" (RPM) should result in a little charge to "PLUS"

As you move again, ammeter should charge some, then drop back to center.

If the battery is in good shape, and charged, and if engine starts quickly, ammeter should charge "hard" for a short time, a minute or two. If it does not drop back, get a voltmeter and check the battery "running" voltage at a "high idle" or in other words an RPM to simulate "low to medium" cruise.