I'm just telling you right now, all the going cheap on your charging system is going to get you is dead batteries and heartache at the end of the day. It's not that I'm any smarter...I've just played the game for the last 8yrs of living-aboard on the hook. A good high output alternator with a smart regulator to me is as important on a cruising boat as a compass.
Amen brother. You may be okay while you are at the dock
but once you get into the hinterland you need a very good charging
system and good deep cycle batteries. A 55/80 amp stock alternator
and combination marine
batteries will destroy your soul once you get past the length of an extension cord.