Multiple answers. Most of them NO
IF the battery is like 95% full.. Perhaps you can.
If the battery is 50 percent full. and you have the proper size 3-Stage converter (Roughly 1/3 of the battery's C/20 (20 hour) amp hour rating) then it takes about 6 hours. perhaps a bit more or less.
Now in theory you could put a big whomping battery charger on it and give it a fast charge. But this is damaging to the battery.
Best opton.. Spring for say small inverter generator someone in the 1200-2000 model number range. That same gallon your ONAN (and mine) burn every hour will last you all day.
