TMS DC Axial Fan 24/48v 1.5a 36w Brushless QG8038H2B

You can series 2 of these fans for 48v applications.

These are expensive elsewhere online. They were recovered from battery packs and are guaranteed to work like new. This is a legitimate fan, puts out a lot of air, and is trusted by very popular brand battery makers.

You'll be a big fan of this fan (pun intended)

9400RPM