Keth, you don't say which engine you have.
I faced a similar choice, and have a Yanmar 3GM
. Here's what worked for me:
A 3/8 inch section belt is good for a reliable 80 HP. I didn't want to convert to serpentine belt either, so used this to determine alternator output.
Alternators with a Yanmar
mount were not ubiquitous but eventually worked with a company called BD Electrical
), who subsequently released an 80 Amp version with Yanmar mount lugs. It also has the electric
Since I also increased house battery
bank to 400+ AH, I also decided on an external (Sterling) regulator, which, over the past 8 years of summer liveaboard
use, has performed very well.
Subsequently, I had to increase the wire gauge, of the alternator output to the starter solenoid terminal. (ask me how I figured that out).
My annual PM schedule specifies replacing belt every second year., but they've not had any noticeable excess wear so far.
Hope this helps with your installation
. If you have questions, please let me know.