Ender 3 S1 Pro fan voltage ???

Today i wanted to replace the parts fan with a Noctua 40x20 12v fan with a buck converter. Setting the fan speed to 100%, the fan voltage is about 6.5 V max on the output of the MP1584EN Mini Buck Converter. The input voltage is only 12-13V not 24V. The stock fan is 24V. What is going on?

They probably used a 24V fan on a 12V line.

The result is a slower, but also far more quiet fan. This is a common technique if you only want to use cheap fans, which usually are noisy.

A potential risk is that the fan may not spin up, when powered up. When it gets older and due to being under powered and a little “rusty” it has trouble to deal with the initial spin, but since this happens far beyond any warranty, so they don´t care.

So you can connect your fan without the buck converter.

I already did connect my fan directly but its not going at full speed (5000rpm) and at 80% it does not start at all (to low amp?). I am not sure but from what i have seen on yt, the ender 3 S1 (Pro) only has 24V.

To get 24V you need a boost regulator. Something like this.

HiLetgo XL6009 Boost Module DC-DC Adjustable Module DC3.0-30V to DC5-35V Output Voltage Power Converter Circuit Board Module 400KHz https://a.co/d/22pblnG

It will draw about 2x or more current, possibly more because fan load increase.

Voltage is adjustable with pot. Set before using, so does not exceed 24V. They often are set max, when you get them.

Turns out it was the printer firmware. Manually setting the fan to 100 is somehow not 100% fan speed (24V), setting the fan to 240 is about 24V.

Actually fan numbers are 8 bit PWM, 0 - 255. 255 is 100%, 127 is 50% … PWM controls voltage by duty cycle.

Thx that makes sense.