Hi,
I did a very similiar setup as described here. Thankful for the content!
https://electricvehicleforums.com/fo...23/index3.html
Everything works except the PWM control of the fan. No matter where I set the PWM controller I end up the fan blowing full speed. I tried various freqs and duty cycles found here on the forum, but none works.
I also used a relay to separate the PWM and 12V feed for the fan from the cars feed. When the grid charger is on -> the relay is on -> the external 12V and PWM is fed to the fan. When grid charger is off everything goes back to cars feed.
When running the car in daily use the fan doesn't operate at full speed, just at a very low speed.
Anybody has any idea what else could be tried?
Thx.

 

It turned out the pwm to be a TTL signal out from the PWM gen (2 channel pwm gen from Aliexpress). I had to change that to 12V and now it works fine. I've set the freq to 200Hz.
Below is how that could be done on the device.