A "claw pole" alternator typical of all automotive style alternators, by design are A VOLTAGE REGULATED CURRENT SOURCE...Period
That means they are designed to provide a constant voltage at the required current demand of the design power requirements.
They were never designed as a current first, then voltage limited device.... Period.
This means they are not by design battery chargers. Each and every automotive alternator specked for an automotive design, is to provide a constant current, voltage regulated to an design onboard power system.
So that means when you install a bumping-thumping sub base wolfer sound system, into a factory design, that didn't include the sound system. YOU are taxing the system beyond warranty. In other words you will cause a brown-out on the design system.
Now that we got that straight, can an alternator be a battery charger
The answer is yes, if by design.
NO, you can't just Willey-Nilley and alternator into a battery charger
But you can create a battery charging system from an automotive style(Claw-Pole Alternator) if it's by design.
When you open the box of a standard automotive alternator, the first piece of paper you pull out, Will, state if the battery is less then 70% SOC, remove the battery to a external charger, and re-charge before install of the alternator...why??
Because, they assume that you purchased the alternator, that was specked by the design of the OEM power system.
go figger.....it's not a battery charger.
Now you expect a boat manufacture, whom spends as little money
as possible on ----On-board Power Design--- to provide you with an automotive style alternator, that meets the requirements of a battery charger...
I say don't hold your breath.
That is what boating forums
are about...everybody gets to say how they think an On-Board power System, should be designed, even if it's just hearsay.
Hell it doesn't cost anything, or does it???