How much amperage can an alternator support? no really...

[LL - NY]

Current cannot flow if there is nowhere to go. It's called resistance. Every
load has some.
And, technically, HP is HP, all the alternator does is convert it
(inefficiently, I might add, read HEAT).
So the alternator has to be designed with a target RPM in mind for it's max
output. However, it also
needs to be able to supply, at the minimum, what the car needs at low RPM.
So, how is this done?


More turns in the coils WHILE dealing with the fact that small wires have
more internal resistance, a nice
balancing act. Glad I never had to design one of these (or an electric
motor, same issues) . Add in packaging, and it becomes tougher. Of note, the
BMW water cooled alternators could fail because BMW felt that the improved
efficiency of water cooling allows them to push the alternators further.
Seems like it's a failure.

The fact that at a higher load there is more HP (remember, inefficient, i.e.
HEAT) being exchanged. If the load, due to resistance (as in, less items in
the circuit, remember that in a parallel circuit, resistance is the reciprical
of the sums of the recipricals of the resistance of the individual loads) is
low, less HP is transferred, less heat, less wear and tear on the
alternator. More HP, more Heat, more wear and tear. And yes, as the loads
increase, the greater the need for HP, therefore the greater the need for HP
from the engine. This is why the Euro Mini's and the C6 Vette electrically
de-couple the alternator under acceleration, to reduce the HP demands for
the electronics (which on the short term can draw from the battery) and save
the HP for, in the case of the C6, acceleration, in the case of the Mini
(Europe only, BMW felt US customers would freak out if their car shut off
(which it also does) when ever the car came to a stop. Dumb 'Mericans, or
Dumb Marketers, don't know which.) improved fuel economy and reduced overall
emissions. Now I suppose, I could trim this post..... hmmmm.