...such gadgets is unanswered? UPS provides power backup for a short period of few minutes only.We want DC power backup for max/entire duration of power failure.Any More Inputs?
If you want power for a full duration of a power outage you buy an electric generator. Here is a small one at 1500 Watts peak, 1000W Continuous: http://www.generatorfactoryoutlet.com/gfo/products/MX1500.asp?rt=2
This and similar may be available as low as $160 or so.
It runs on gasoline, and depending on the load could last 5 or 6 hours on a gallon of gas. They output 120V AC