Nice! You basically made a free version of this? https://www.amazon.com/gp/aw/d/B00YGLTOXI
I’ll have to keep that in mind - I too have a spare case fan (quiet!) and plenty of batteries. 
The_dAY, I have one of the fans which you have linked in your original post. It works quite well.
These things have no safety of any kind. I have them and use them regularly, however the batteries are charged externally in a Nitecore d4, not via the included USB port.
Do not plug this into your primary computet’s usb port for charging
Thanks for the idea!
Now imagine using a 140mm, high-CFM fan and driving it to full 12V:
This thing is rated 83cfm at full RPM, which is a LOT of air!!
Thanks all for your impressions/comments and the link to the reddit review.
I’ve noticed some fans will have smaller blades than others, best to get one with full size blades.
Also agree about charging the 18650 in a seperate charger instead of through the fan, for speed and safety concerns.
Can’t seem to get over that $50 amazon minimum though. Been looking for other stuff to add to cart but nothing interesting or needed…
Just noticed Jaxman has a 18650 fan in their store:
http://www.aliexpress.com/store/product/18650-battery-fan-with-night-light-USB-rechargeable-Max-4W-strong-wind/1812094_32709009414.html
