dogdays my friend, I'm gonna share this experience about Amm vs Volt.

Once I got a misterious discharging reading did need to rev it up quite high to be able to get charge reading. Took a multitester and while idling, getting discharge, the Multitester got me around 18-20 volts!!! how that was posible ?

then to be sure, I disconected the batt and engine stalled.

So which reading was the truth one ? Voltage or Amperage ? Both were truth, but the batt was getting discharged with an alt not able to hold the engine on, so the real deal was the ammeter reading.

The fail was one of the rotor vent vanes meeting with diodes bank/stator terminal while spining, causing a short.

If I had a voltimeter my mind was told me I was overcharging and not discharging! True both told me something was wrong, but the reality was the discharge deal.


EDITING to add info:
the ammeter is a magnetic gauge, doesn't read volñtage based on a resistance. The needle moves when gets magnetic fields variation with the load flow.