Generator Gas Usage, AC, and Battery Charging

BlunderLust wrote:
It seems the Yamaha and Honda 2000 WATT Generators have the lowest fuel consumption. I have read these generators run about 8-10 hours on one gallon of fuel.

Have owners of these generators found the 8-10 hours per gallon to be correct?

I am pretty sure these will not run the 13.5K roof mount AC but I am thinking I could add an auxiliary 8K to 10K window unit while boondocking.

Does anyone have experience with using either (or similar) of these generators with smaller AC units?

Powering a window AC would be great but my main need is to charge the RV batteries. I have read some battery types charge more slowly as the charge approaches 100 percent.

Does anyone know how many AMPS these generators can dump into a battery per hour?

I think the battery type, LITHIUM, AGM, GEL, LEAD ACID impacts this as well. I am OK with paying a premium price for a HONDA, YAMAHA if I get better fuel economy, and product life. But I am a bit concerned that to charge the batteries I might need to run the generator at full power. At full power the fuel usage could increase such that I would be better off with a larger generator which might actually cost less.

The DC outputs on any of these generarors are completely useless. They are extremely low current for the fuel you put into them, somewhere around 6A with ECO mode Off. Plan on a good 3 stage external,charger for any of your battery escapades