The scorching summer often results in frequent power outages. Having a mini battery-operated fan that can run for hours is excellent, especially for young children. Just using an old computer CPU fan and a few batteries, you can make a desktop fan. @Dientuk69c shares how to make a mini desk fan for just a few thousand [Vietnamese dong]. Chip fan, CPU fan, 18650 3.7V battery connected in series or parallel from 3.7V to 12V for the rotating chip fan. The more batteries connected in parallel,