Fans

[BrianG]

Generally, the closer the fans working voltage to the supply voltage, the better. If you are running 12 cells for your main batteries, that is at least 14.4v (as high as 16v on a full charge). A 12v fan will fun faster and may wear out sooner. Any more cells just makes it worse. Running a 5v fan on a 6v pack is the same idea. A 5 cell pack can run as high as 7v on a full charge. They will run, just a bit fast. If you are running a UBEC, that only puts out 6v, so it will be closer no matter the charge level of the batteries.