Originally Posted By: Keroppi

So if anything is connected to either post on the Ammeter, it will be hot? That is good to know. That means it's always just measuring the total current in the system.

I will show some of my ignorance when I looked at the coil, it's actually marked + and - on the posts. Positive goes to the Ammeter, negative goes to the distributor.


Look closely at the wiring diagram in your Service Manual. All of the loads attached directly to the Ammeter are wired to the + side. The only connection to the - side is the voltage regulator Bat terminal. This is because loads consume power and cause the Ammeter to lean in the Discharge direction. Leave the headlights on without the engine running and the Ammeter will lean further and further toward DIS eventually falling on the ground.

Also, take note that all of the loads attached directly to the Ammeter are all switched - ignition switch, light switch, etc. This is because the Ammeter is a direct path the battery. The positive side of your coil is wired to the ignition switch - so the coil is not energized until the key is turned on. Only a constant load accessory like an Electric Clock is wired directly to a Bat terminal.

Originally Posted By: Keroppi

How is this effected by the Alternator? The Alternator is always providing current no matter how fast the engine is running, even at idle. Does this mean the needle stays constant when an Alternator replaces the generator?

That is a common misconception - the alternator is not always supplying current. There is an internal regulator that is measuring battery voltage. When the battery reaches 13.5 volts (typical set-point for a 12 volt regulator) the alternator is switched off. If it did not switch off the battery would boil over.

In a vehicle with lots of accessories that draw a lot of amps the alternator will cycle on and off as the voltage frequently drops just below the set-point and then returns to the set-point.

Your expectation of the needle sitting dead center is likely with just the engine running.

I am running a 6-volt alternator and that's what I have observed. But if I turn on the head lights it will show a slight discharge. And my turn signals cause the needle to the tap in time with the flasher.