DIY ESS - Variable Fan Speed with PWM & Thermistor

This morning, I am experimenting and trying to find a simple solution to make the ESS Fan accelerate when the temperature in the Metal Cabinet is rising and slow down when it is back to an acceptable value

As you already know, the fan is controlled by a PWM kit that I soldered 2 weeks ago and I can adjust its speed using the PWM kit potentiometer; That is already a good step, but I would like to make it better

In the Arduino starter kit I got a year ago, there was a Thermistor and I used it between the negative and the variable output pin of the potentiometer: It looks like it is working, and you can see the pictures and video where I increase or decrease the fan speed using an ice pack and a soldering iron to make the Thermistor resistance change based on the temperature changes

Thermistor temperature

Ice pack temperature

Soldering iron temperature

Cooling the Thermistor after heating it up

Fan speed changes ...

DIY ESS - Temperature Control inside the Metal Cabinet and Detailed Components Layout

I now have a thermometer in the cabinet to check the temperature on regular basis, and it is staying around 25°C, which is fine

Today, I am charging with 4 chargers only (you can see that on Wattson Anywhere link on the left)

4 chargers ON

GTIs OFF

Fan blowing, and 24°C

DIY ESS - Fan holes drilled & spinning test

A bit noisy, all this drilling, but it is done !

First: markings

Second: small holes drilling (2.5mm, easier)

Third: bigger holes (7mm)

A little test with a 12V AGM battery: it blows well, enough to egt all the hot air out when charging or discharging I think; And it is very quiet :-) with or without the doors closed

Two extra holes to put screws to hold the shelf, otherwise it just falls (!)

I bent a little bit the base of the second shelf and put it on top of the bottom metal sheet

Bending on this corner side