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The stock Ender 3 fans are quite loud, so we will replace them with quieter 12v Noctua fans. This is made easy by the onboard 12v regulator on the Mini 5+ removing the need for an external buck converter.

The replacement fan is a Noctua NF-A4x10. This is a 40mm x 40mm x 10mm fan capable of pushing a rated 4.8 CFM at a mere 18db. This same fan will be used for the hotend as well and is the same fan used on the Prusa MK3.

The fan comes with a convenient way of splicing the fan to an existing connector which Noctua calls Omnijoin. This uses 3M Scotchlok terminals that create a physical and electrical butt splice connection between two pieces of wire.

Simply use the included plug on one end, and snip the existing fan wire for the other end. Match black to black in one Scotchlok connector, and red to red in the other. Use plier to push down the button and lock them in place.

If you are not using Noctua fans and don't have the Scotchlok connectors, you can simply snip the ends and resplice new plugs or use a soldered butt joint to extend the wires of your fans.

The fan orientation in the first image has the fan blowing into the enclosure. Unfortunately, the grates on the enclosure greatly reduce the amount of airflow for the Noctua fans lower speed. Therefore the fan was flipped to draw air out of the enclosure. In order to keep wires clear of the blades a printed 40mm Fan Guard was added.

Alternatively, you could use a hand file to remove sections of the grates from the case plate to clear the path for the fan blades. Just be sure nothing is likely to enter the blades. Consider adding a less restrictive grate.

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