I have the costco 1000 waat Xantrex inverter. I coupled it with a deep discharge battery and a charge maintainer battery charger. This setup is able to provide up to 1500 watts for a few minutes, 1000 continuous.
It's almost never worked as I wanted it to.
I'd had it almost 2 years when we had a power outage at 5 am. The beeping UPSes woke me, so I powered on the inverter, ran an extention cord 30 feet to the coffee maker and within a minute the UPS was beeping. I assumed it was the overload alarm. It shut off before the coffee was finished. I had almost 1/2 pot of coffee.
Later, when we had power back and time to investigate, I realized that pulling around 100 amps from the battery (to get 1100 watts to the coffee maker) was murder on the battery. The charge maintainer I'd had it hooked to was inadequate, and when I checked the water I was shocked to see that the cells were dry. The charger had boiled off the water. The constant beep was a low voltage alarm, not the overload that I expected.
A new battery was not in the cards; I topped it off and got it back into service, but it never recovered from the high curent with inadequate electrolyte. I bought a 4 cup coffee maker that pulls only 500 watts or so, and used it during the next outrage. The low voltage alarm came on in only 10 minutes, so I recycled the battery and set the inverter aside in case I ever need it again.
I've since bought a gasoline based battery. Well, it converts gasoline to electricity. The 6500 watts continuous, 7500 peak, electric start generator will handle 6 coffee makers at once.
I figure the use I got from the charger + battery + inverter came to about $50 an hour.
Daniel
). Last time at Costco there were 2 different Xantrex models, one was a 1500w model which I think was like 
