Series/parallel charging question for les tinkerers grandes

Here's the generator we use ... unfortunately this particular one is in the wrong country ... but you could look around to find one used (they're a discontinued - but legendary - Honda product), cheap, and available in the U.S.:

http://www.gumtree.com/p/generators/honda-ex650-suitcase-generator/1123007002

Here's a spec chart showing how it stacks up against other discontinued Honda generators - from the chart, notice it's noise level - as compared to the current Honda EU1000i generator's noise level:

http://www.tappedin.com/hop/html/litegen.htm

Here's one model of the fuel cell RV battery charging technology I was referring to - methanol powered. Note that's it's output power is 28 VDC (check the Tech Specs tab):

http://www.protonex.com/products/m300/