Dash lights will not turn off!! 72 dart
Its an all too common belief. As you can see your ammeter did not cause the problem.
The ammeter only shows what flows in and out of the battery.
Jeeps with electric winches or plows can have issues with the battery circuit because of the heavy load directly on the battery - the alternator tries to help and then has to recharge the battery. The circuit sees high current for extended periods of time.
On your car, unless your running a big amplifier or electric pumps off the battery, the only current through the ammeter is during start, and when recharging. On standard '72 wiring the alternator supplies power to the welded main splice. From there is goes to the main feeds. Obviously if the battery needs recharging, it goes there too.
@RedFish has posted that in his experience as a tech (including dealership) some of the early 70s model have water leaks in that area. Oxidation and corrosion will effect all exposed connections and that will cause ammeter issues. Also some of the ammeters seem to be more prone to problems. The main problem reported has been the studs getting loose. They're pressed into the plate. So if they get loose, they will only get worse. Some people have soldered them.
In your specific situation we know the alternator was providing power at 18-19 Volts.
If the battery is offered power at 18 Volts, current will flow through it and it will overcharge and boil the acid.
If the battery is already low, then it will overcharge, get hot and draw lots of current.
The ammeter will be over 20 amps Charge and stay there, sometimes even at idle rpms.
20 - 40 amps is not enough to damage anything immediately, but is plenty to get connectors and wires hot if it continues.
Keep in mind the alternator output line is carrying the power to recharge the battery in addition to everything else that needs power: Ignition, alternator field, brake lights, etc.
Its an all too common belief. As you can see your ammeter did not cause the problem.
The ammeter only shows what flows in and out of the battery.
Jeeps with electric winches or plows can have issues with the battery circuit because of the heavy load directly on the battery - the alternator tries to help and then has to recharge the battery. The circuit sees high current for extended periods of time.
On your car, unless your running a big amplifier or electric pumps off the battery, the only current through the ammeter is during start, and when recharging. On standard '72 wiring the alternator supplies power to the welded main splice. From there is goes to the main feeds. Obviously if the battery needs recharging, it goes there too.
@RedFish has posted that in his experience as a tech (including dealership) some of the early 70s model have water leaks in that area. Oxidation and corrosion will effect all exposed connections and that will cause ammeter issues. Also some of the ammeters seem to be more prone to problems. The main problem reported has been the studs getting loose. They're pressed into the plate. So if they get loose, they will only get worse. Some people have soldered them.
In your specific situation we know the alternator was providing power at 18-19 Volts.
If the battery is offered power at 18 Volts, current will flow through it and it will overcharge and boil the acid.
If the battery is already low, then it will overcharge, get hot and draw lots of current.
The ammeter will be over 20 amps Charge and stay there, sometimes even at idle rpms.
20 - 40 amps is not enough to damage anything immediately, but is plenty to get connectors and wires hot if it continues.
Keep in mind the alternator output line is carrying the power to recharge the battery in addition to everything else that needs power: Ignition, alternator field, brake lights, etc.