Generator run at different speeds

I have a 2005 Fleetwood Excursion with the same generator. With nothing else on, the generator rpms will change and the needs of the batteries / battery charger change. The rpms will start off somewhat higher when the batteries first start charging - drawing a higher amperage. Then as the batteries have been receiving a charge, the charger amperage decreases and therefore the generator rpms decrease.

I don't see any problems with your generator. The same thing happens when the A/C or microwave comes into use.

Bill