I didn’t see the start of this thread, but I think I can contribute.
These stock alternators are aftermarket, not made by Yanmar, despite the sticker. Do some searches on the Internet. You can buy a 50 amp for $120 or so. There might be 80s out there, too. The same one with the Yanmar sticker will cost you $800.
Even though it seems illogical, there’s not a large difference between the 50 and 80 stock units unless you have a huge battery bank.
That’s because the charging rate slows as the alternator heats up and because the acceptance rate slows for your batteries as they fill up. You might start at 80, but you’ll soon be at 50 or 30 or less.
My alternator is not fused. It is wired to the common pole on the switch. If you switch through off when the diesel is running, you kill the alternator. I have 200 amp fuses on the positive battery posts to protect from short circuit and fire.
Sonas, 1998 Catalina 320
Tierra Verde, Fl.
Sent from Mail for Windows 10