I got my wife one of the 10" triple power source O2Cool fans. We've tested it purely on 12VDC (I've no intent of putting batteries in it), and took it on our Apocc-eclipse trip but didn't need it. There have been times where we needed one in the past, so I'm sure we'll need it in the future at some point. It is reasonably quiet and moves some air. Aiming of it will be important. Don't expect a house box fan volume of air and you probably won't be disappointed.