I recently bought 2 cooling fans (Maglev Cooling Fan, 40mm by 40mm by 28mm with 3 Pin 3 Wire Connector 12V DC, 2.8 W, 9200RPM, 17CFM). I am actually not planning to hook them up to my machine but use them for another project. I am trying to hook them up to an external (small) battery source but am coming up short and need some advice. Ideally, I would like both fans running at peak performance at the same time. I tried 9 volt batteries but am not getting the fan speeds. I am wondering if I should hook them to a usb cord and plug them into a portable charger (5v, 2.1A output), but I would not know how to connect a usb cord to a 3 pin fan, or if it would even work. Any suggestions would be appreciated.