I used to have one of these: 12v bilge pump until we moved to a house without a basement.
But I don't really recommend it. You have to be there during the flood, and if so, you could just use a portable generator to plug in the usual pump. (Which I didn't have at the time)
My next door neighbor installed a 12v pump, but just like an antique car that sits in the garage, maintaining the battery was a pain. They moved before needing it, and our neighborhood stopped losing power so often after a BGE rework of the area. Last I looked, it was shown on the Home Depot site.
I have other stories too, but the bottom line for me was that I felt much better being able to pump out with power from my car, or from a genset, or whatever. Otherwise you just stand there watching it happen, and that is rather demoralizing.