Invertors are usefull for short term power. A sugestion, if you have a truck or SUV where you can mount it under the hood or in the bed, you can add a second battery and an isolator. The car aduio guys like like the Optima ones and they make a deep cycle. Then hook the invertor off the deep cycle and you can run it dead and still start the truck and charge it backm up. Remember when buying invertors they have a peak and and continus rateing. So make sure you buy big enough for what you need, but not too large as i understand the larger usually get less efficient. I'm thinking of getting a couple of the little 75w ones that are sold for $20-$30 and put one with my cordless drill/saw/flashlight combo and one with my laptop to supplement the 300/600w in my truck. If I ever had to pack and go in a hurry, the laptop is one of the primary things I would take as it has all my receipts/pictures/etc all scanned and stored there as well as a set of backup cd's in the bag, so its high on the priority to keep with me.