I know you are aiming to charge your batteries with a generator or two, but I'll add another voice for solar. My 272 watt system keeps my 2 six volt batteries charged without gas or noise. After a cold night my bank is usually down to 75-80%, but is back to 100% by early afternoon even on mostly couldy days.
Barb (RVM18), Sena (capuchin monkey, RVM Head Mascot) & Lily (Maltese/Yorkie)
2011 Shasta Cynara 230F & 2012 Smart Car toad, 272 watt solar system
The Journey is Our Destination. Full-timing since 5/18/2011 and loving it.