Soft Shutdown During Power Interuption

I need to find the right combination of electralytic caps to connect to a video camera. They will supply power in the event of a power failureto the camera. Right now I am using a 35v 470µF, I think I need a cap that is close to the battery voltage I am using. Like around 5v, because the Propel batteries I use are 3.7v. Maybe I'll put a picture on here later. I haven't been on here in a while, I need to get back into it. I notice I can add video, interesting.