[D.Kreft]

On Feb 27, 9:56 am, "Mariachi" wrote:

if the voltage of the alternator goes below the voltage of the
battery, then the battery does supply current for whatever the
alternator cannot handle...

Careful, sir. You've made a misstep three words into your post.
Because the battery and the alternator are wired in parallel, it is
physically impossible for the voltage at the alternator to differ from
that of the voltage at the battery (assuming negligible internal
losses in the connecting wires).

Remember, that at all points in a parallel circuit, the voltage will
be identical everywhere, but current draw may differ at various points
in the circuit. In *series* circuits, the current is the same
everywhere, but the voltage drop across each device is what may
differ. Put into formulas:

Parallel:
Vs = V1 = V2 = V3 = V4
Is = I1 + I2 + I3 + I4

Series:
Vs = V1 + V2 + V3 + V4
Is = I1 = I2 = I3 = I4

Where 'Vs' and 'Is' are the voltage and current at the source,
respectively; and where 'V#' and 'I#' are the voltage and current
measured at each device in the circuit.

-dan