I know of an off grid setup like this. They first used a propane powered generator to charge the battery bank, which wore out the propane genset. They then switched to the 2 cylinder listeroid. As you might expect, there are substantial losses when using AC power from a generator, into a charger, into a battery, out of a battery, into an inverter and end consumer. From what I was led to believe, the fuel consumption went up by about 30% when charging the battery bank/inverter setup vs. using the listeroid power directly.
Put another way, they discovered it was clearly most efficient to use a modern high quality, low fuel consumption diesel generator, and directly power the multi dwelling off grid compound. The Listeroid was not as efficient as a modern diesel genset.
Eventually, they chose a set of tracking solar panels to charge an upgraded battery bank and have not looked back. They simply use the high power consumers during the day when the sun is shining.
EDIT: It's generally said that a Listeroid consumes 0.125 gallons of fuel per KWH. Modern diesel generators consume 0.09 gallons of fuel per KWH. Typical modern diesel gensets are about 28-30% more efficient than a listeroid.
I've said this before, but the real advantage to the Listeroid is the 6/1 and operating it in the middle of it's operational output, consuming a gallon every 6 hours. Modern stuff is not sized to run in that operational range and will therefore consume much more fuel when making 1500W.