12v fan control (preferably varying speeds)

Devices & Integrations
1

I’m looking for a way to control a 12v fan through smartthings. It’s a 3-wire PC fan, but I’m using it to cool an enclosure. I’d like to be able to adjust the voltage to change the fan speed, but I can live with on/off only if I have to.

I know the MIMOlite can do on/off, but I’m curious if anyone knows how loud the relay is when it changes state.

Is there a device that can take a 12v input and then vary the output between 0v-12v and is either z-wave or zigbee? I’ve had no luck searching for one.

2

Check the specs for each model to be sure, but some of the roller shutter motor controllers should be able to do this as long as the fan motor isn’t too powerful:

3

Thanks for that idea. The fan is only 1.44 watts at 12v.

I noticed that the Fibaro RGBW controller is using PWM outputs. Perhaps if I got a fan that has a PWM input I could use that? Their manual says it works with fans, but doesn’t give any further detail and I can’t find anything online where anyone has actually used it for a fan control. I also read a lot about how the PWM frequency can cause fan humming, and I certainly don’t want any extra noise out of this.

4

Yeah, I don’t know. @TheSmartestHouse Might have some ideas, they are the retailer I linked to and are quite active in these forums. :sunglasses:

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5

The RGBW controller probably won’t work with a fan correctly, we’d recommend the Qubino Dry Contact Relay for on/off control: https://www.thesmartesthouse.com/products/qubino-z-wave-plus-flush-1d-relay-module-zmnhnd3?variant=29086491473

Unfortunately, we don’t know of a Z-Wave product that would allow for speed control of this type of fan.

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6

Following up. I already had a regular 12V fan. I ordered the exact same fan that also had a PWM input. I asked on the Fibaro forums if anyone had any insight and was told that a regular (non-PWM) fan would work on the RGBW controller, just put the black wire on a PWM output. So I tried.

  • The regular fan connected to the Fibaro RGBW controller just stuttered and hummed and didn’t actually spin.
  • The fan with the PWM input spun fine and it changed speeds, but anything other than full speed had a bad hum on it. Also, it was not possible to completely stop the fan.

The result is that the RGBW controller does technically work with a PWM fan as their manual states, but it’s not good.

I’m going to keep the PWM fan just in case something else comes up in the future, but for now I’m just going to use a relay.

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7

Thanks for sharing your findings! We’ll pass them on to the Fibaro team as well so they can correct their documentation regarding the PWM fans.

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8

@howardtopher Did you find a solution for multi-speed? I’m trying to accomplish the same thing for my server cabinet.

9

Not really. I’ve only ever found on/off options. The only thought I’ve had is something like a 12v to 5v or 9v step down to add to the relay, but that doesn’t really work because the converter is not variable either. Right now I just let my fan run full speed when it needs to.