High capacity alternators
As you see, you don''t even finish to think your question, but Jack answer is almost already posted. Ha ha ha!!
Ok. I have gone through that.
1. Is not the same putting a 150 A alternator to a 115 perkins than to a 28 hp volvo. So I assume that if you are considering a 150 A piece, your auxiliary is closer to 100 HP rather than to 30.
In any case, if such piece of alternator is to be charging 60 Ah o greater current for more than 15 minutes (This is replacing a 50 % depleted 450 Ah bank), you should consider having twin pulleys, good ventilation for the case, and assurance of the varnish quality in the windings. Implicit is the requirement of a good three stage external regulator.
Having said that, the forest, as Jack describes, is a very complex and expensive instalation, involving not only the electricity side but also the engine too. Now I would like to discourage u in trying to reduce your budget by US$ 100 or 200 in the alternator piece, since the value of the forest may be 100 times that. This mean that I followed the number 1 route suggested by Jack.
However, my 110 Balmar run by a 60 HP VOLVo, has only one pulley. Meaning that I almost never want my 450 bank be depleted in more than 40/50 Ah between charges. (I still carry 10 replacement belts onboard, and when the RPM needle stops is the moment to stop engine and replace the belt) Any time at all i''ll upgrade the pulleys.
Regards to u both