Got a Costco 2k generator for a long weekend at Pismo. The onan 5.5k would run the inverter/charger at 150 amps (its max)(in the morning), the 2k would have to be throttled to ~100 amps. I ended up running the onan until the charge current dropped to about 75 amps, then switched to the Costco generator for a few hours. The onan is a lower, bass noise, then Costco is a higher pitch. The Costco generator burned about 1/4 the fuel as the onan, but even on the beach at 5 feet, wouldn't start the 15k ac.