Alternator

[sd455dan]

edit
The sense wire can help keep the charging voltage up a bit higher when connected to the fuse block supply buss B+
On some vehicles where you are normally going to see the largest voltage drop with all accessories on- like lights, electric fuel pumps fans and such.
This is where the sense wire is terminated on many 1970s GM vehicles.

 

[Keoke]

Hi Sd,
You make a very good point about the fuse box buss bar as being a good spot for VR #2 sensor wire. This spot along with bat cable stud at starter solenoid was used on older GM vehicles.
Please give the following thought.
With vehicles running there are only two sources of circuit voltage. One is the battery at 12.6 volts and the other is the alternator (13.4 to 14.8 v).
The highest overall voltage, minus voltage drops will be superimposed everywhere. Surplus alt amps, after load feeds, will move toward the (chg) battery (12.6v) which is at the end of the line.
Accordingly, the lowest vehicle voltage found while the alternator is charging is always at the battery. If the overall circuit voltage falls below 12.6v then voltage and amps would flow from the battery to cover the alternator's deficit load. Of course in this case bat voltage will fall below 12.6 v.