Your generator may be deisel but I doubt it, there is probably a gasoline tanks close by, the invertor will convert your gennys 112v to 12 volt to charge those batts, then with the genny not running, you may run 112 off the batts as your invertor converts 12v battery power to 112V outlet. pretty cool really. you have to know how everything works, so that you don't run out of power some where. my guess is there is a spot to plug a big 30 or 50 amp cord so you can run off shore power also.
take as many pictures as you can, and post them here, if you need help posting pictures email them to me blizznd AT gmail DOT com and I'll post hem here for you.
the only dumb question is the one that isnt asked. were here to help share what we can
2001 GMC 6500 Topkick, 22' box, dropped frame, designed to fit into a 9' garage door. 3126 CAT 6spd Man Lo-Pro 19.5's w/ 3.07 rear axle ratio