I actually have one of these. I never used it on battery, so I can’t speak to that, but when plugged in, it’s a nice little fan. I used to hang mine in my little bathroom window. Haven’t used it for a couple of years, but it lasted me a few years before that, and was working fine when I put it away the last time. The only complaint I have about it is that it takes up a considerable amount of surface space if you want to set it up on a surface.