Smart charge is in the alternator AND ECU, they "talk" to each other.
The ECU tells the alternator at which voltage it has to charge,
could be over 16 volt at low ambient temperatures.
The grey wire is also going to the ECU (so 2 wires to ECU).
The red wire is a sense wire.
It will now be charging at 14 volt, so a bit lower than normal.
The 50 amp quote is rubbish, the current depends on what is needed
to charge to 14 volt at the battery. If the battery is full and there is no drain
the current will be less than 15 amp.
A lot of alternators are replaced because the mechanics don't understand
this system.