Sump Pumps

I have a sump hole in my basement, I have a primary sump pump hooked up as well as a secondary as there is alway water in the sump hole. My concern is if the power should go out my sump pumps will not work resulting in my basement flooding. Is there a sump pump that can be use that is plugged in and if the power goes off it will operate??? There are time when I am away from my home and I want to insure that the water is removed from the sump hole...

Thanks Dave