Thanks for spending time to reply to me - I really appreciate it.
At this point, I think it's beneficial to add that I have some basic understanding of electronics.
I know what PWM is. Just wondering if I am oversubscribing to the idea that PWM's are more efficient (especially around lower RPM)
I know 5+5 is not 12. Actually I don't even understand why you might think I said anything like that?
A 18650 is typically around 3 - 4v. So, two 18650's will still have a boost converter.
What I was really asking is whether it is feasible (and therefore I can expect to find an off the shelf product) to boost to 12v from a single 18650.
As for 5v, wondering if the quality of those fans can match the 12v fan I mentioned? That one is really quiet and blows a nice amount of air.
I already have a loud AC fan, I am trying to build something better (to reiterate: I am not building a fan, the fan part is just one component of the system I am working on)