How to lower the fan speed on ifan04-h?

[tomber71]

I have flashed esphome-ifan04 on my Sonoff IFAN04-H and wounder if it's possible to lower the RPM of the fan?
On high the speed is to fast. Low and mid is ok.
Is there anything to modify in code or do i need to solder new caps? If so, which caps and what value?

[rh1rich]

At high speed the fan output is directly connected to the power input through relay 3. That can't be changed.
Mid and low speed are controlled by relay 1 and 2.
Relay 1 adds a 2.5uF capacitor between input and output.
Relay 2 adds a 3uF capacitor between input and output.
If relay 1 and 2 are active, both capacitors are in parallel, so the resulting capacitance is 5.5uF.
If you want to reduce the speed of the fan, the capacitance must also be reduced.
E.g. you can replace the 2.5uF capacitor with a 1.5uF capacitor and change the code to only use relay 1 and 2 for the 3 speed levels.
Low = relay 1 --> 1.5uF
Mid = relay 2 --> 3uF
High = relay 1 & 2 -- 4.5uF

[rh1rich]

Needed changes to the script "fan_speed_set" in the yaml file to use only relay 1 and 2:

      - if:
          condition:
            lambda: return (speed > 0);
          then:
            - if:
                condition:
                  lambda: return (id(fan_boost_enabled).state && (id(last_fan_speed) == 0));
                then:
                  - output.turn_on: fan_relay_1
                  - output.turn_on: fan_relay_2
                  - delay: $fan_startup_boost_time
            - if:
                condition:
                  lambda: return (speed == 1);
                then:
                  - output.turn_on: fan_relay_1
                  - output.turn_off: fan_relay_2
            - if:
                condition:
                  lambda: return (speed == 2);
                then:
                  - output.turn_off: fan_relay_1
                  - output.turn_on: fan_relay_2
            - if:
                condition:
                  lambda: return (speed == 3);
                then:
                  - output.turn_on: fan_relay_1
                  - output.turn_on: fan_relay_2

[tomber71]

This is my solution:
Low = relay 1 --> 1.5uF (44 RPM)
Mid = relay 2 --> 1.8uF (61 RPM)
High = relay 1 & 2 -- 3.3uF (109 RPM)
I am so happy with the speed now.

[xoxys]

@tomber71 which capacitors did you buy? Im struggling to find replacements that fits into the original case.

[tomber71]

I got tall caps from Mouser but mounted them on the side with the legs bent around to the side.
Mouser No: 80-R46KN415040P1M, Mfr. No: R46KN415040P1M and
Mouser No: 80-R533N418050P0K, Mfr. No: R533N418050P0K

[xoxys]

Awesome, thanks!