What youíre describing is exactly how I plan to setup my charging
The plan is to configure my external regulator
to only minimally excite the alternator
below around 1000rpm, just enough to get the tach signal, and then start ramping up the power after that.
This is mostly a consequence of having a relatively big alternator
(80A) on a small engine
(Yanmar 1GM10). I donít want the big alternator dragging on the motor
when Iím putt-putting into an anchorage and/or my slip.
The other reason, though, that itís important is due to alternator cooling
. At low speeds, the centrifugal fan on your alternator isnít going to be all that effective. Higher RPMs move a lot more air, which keeps your alternator cooler.