Have 10W temp dependant fan controller - Need 50W

[pontiacg5]

I have 2 3x140 radiators on a build I'm working on. I'm using an Aquacomputer Aquastream XT pump that has a fan controller built in, but it's only rated for 3 fans, so I'm guessing around 10W at the most? I'm using fans that total around 50W at full tilt, which would probably do bad things to the analog fan controller built into the pump. And yes, it is analog not PWM.

Is there a simple circuit I can build that would match the output voltage of my water pump's fan speed controller? Or even better, one I can buy already assembled?

Thanks in advance!

 

[dostov]

Voltage control: Not that I know of.

PWM: Yes, you can easily find one for cheap.

I'm guessing you're using 3-pin fans?

 

[pontiacg5]

Yeah, I know how to split PWM fans. Unfortunately the pump doesn't have a PWM controller, and I don't want to use the mobo fan headers because they "thrash" or run the fans up high when you do something like opening an app. Really no reason for that since it's watercooled, and I haven't figured out how to stop that yet...

Yes, 3 pin fans. 140mm bgears b-blasters. If I could figure out a water temperature dependent PWM controller that doesn't "thrash" I'd get some PWM fans...

 

[NiHaoMike]

The BIOS settings might let you slow down the fan response. By default, they're probably tuned for heatsinks with a small thermal inertia.

You can make a good PWM controller with a 555 timer. Or an Arduino or some other microcontroller, for that matter. There are even variable speed fans that directly connect to temperature sensors, but they're very rare.

 

[pontiacg5]

I looked around for a setting like that but couldn't find one. I guess it might be possible with software in the OS, but I'd like to avoid that if possible. The Bios just has a few profiles and a warning speed from what I can see.

Anyway, if I were to use a LM350 regulator, pass the reference voltage from my fan controller through two diodes to drop 1.25V and attach that to the reference pin wouldn't I get the same voltage -1.25V on the output of the LM350? I can live with my fans only ever running 10.7V at the most.

Never would I have guessed it would be so hard to control fans based on temperature. What the hell, nobody makes a thermistor driven controller that can run enough fans for the average WC build

 

[NiHaoMike]

Use a microcontroller to measure the temperature, then generate a PWM at about 22kHz to drive some PWM fans.