Voltage regulator overcharging
Here's a couple more filled in as examples:
The voltage of 12.8 is just an example of a fully charged, good battery and switch off. Yours might be a little more or a little less. The point is voltage everywhere should be the same when there is no current flow. Resistance doesn't matter because there is no flow.
Next is an example of Switch in Run, Engine Off.
Randomly choosing 12.1 as the battery voltage.
There is 2 or 3 amps of current flowing. Dashed arrows represent the flow.
Most is to, and through, the alternator field. The coil will draw current until its saturated and then zero. If there is an electronic ignition, that too will draw current with the switch on, but this is a points example.
Small voltage drops represent resistance through the wires and connections that current flows through.
The big drop in voltage will be through the field windings. The voltage on the second terminal will be something closer to zero. The exact amount will depend on the regulator. If the regulator allows full current flow because it senses the system voltage is very low, then voltage in the green wire will be close to ground.
Here's a couple more filled in as examples:
The voltage of 12.8 is just an example of a fully charged, good battery and switch off. Yours might be a little more or a little less. The point is voltage everywhere should be the same when there is no current flow. Resistance doesn't matter because there is no flow.
Next is an example of Switch in Run, Engine Off.
Randomly choosing 12.1 as the battery voltage.
There is 2 or 3 amps of current flowing. Dashed arrows represent the flow.
Most is to, and through, the alternator field. The coil will draw current until its saturated and then zero. If there is an electronic ignition, that too will draw current with the switch on, but this is a points example.
Small voltage drops represent resistance through the wires and connections that current flows through.
The big drop in voltage will be through the field windings. The voltage on the second terminal will be something closer to zero. The exact amount will depend on the regulator. If the regulator allows full current flow because it senses the system voltage is very low, then voltage in the green wire will be close to ground.