All good thoughts. Please don't think that by not responding to your questions, I am dismissing them. Rather I am going back and rethinking and working through each suggestion, learning as I go. Often, when I think I have an well formed response, I find on final reading that I failed to understand something, and I go back and try to educate myself more.
I tend to spreadsheet everything so that I can easily see how different variables affect totals. As I consider each of the suggestions and try to work out the numbers on each of them, I of course develop additional questions. Any additional help is appreciated as I try to formulate answers and better questions.
First, as several people have suggested a genset, I am confounded when I try to find a way to use all of the available energy from the generator to charge the batteries. It seems that a 5KW generator should be able to power a 417 amp charger (I recognize that is ridiculously large, just showing the math), but the largest charger I find is 150 amps. I realize that the rate at which the batteries accept charge is a limiting factor as well, but is there any way to more fully utilize the power being generated by the generator so as to run it as little as possible? As I look at my growing spreadsheet, the disparity between the 5000W produced per third of a gallon of diesel used by the genset and the 150a actually making it into my batteries just really stands out as an inefficiency as I compare options.
Second, can anyone advise current Gasoline and Diesel prices in the Caribbean?
Finally, does anyone have specific knowledge of a H/O alternator that is a direct replacement for the stock alternator on a Yanmar 4JH3-HTE? I have as yet been unable to confirm that anything larger than a 110 amp is a direct bolt-on and doesn't require double pulleys or the like.
Thanks again for the continued responses. My thinking has come a long way in the last few days.