Need help with a mod using Speedfan

[tcclaviger]

I may have to use a chiller to reach my cooling goals so in an effort to avoid condensation but simplify the process I propose the following:

Speedfan reads my MB sensor (It's located down by my second PCIE slot, the coolest part of my case) and it is always a couple of degrees higher than ambient (usually about 2-5C higher than ambient). Speedfan can also control fans based upon a set temp sensor, as I am sure you all know. What I was wondering is if it is possible to use motherboard PWM function via speed fan, to a relay to provide power, then to a dual TEC chiller setup.

Through trial and error I could build a ramp for the PWM control in speedfan to keep the CPU within 5c of the MB temp sensor. I do understand that the water temp will be well below ambient at this point, so the need to insulate the tubing, reservoir, pump, fittings, and blocks will be there, but I am hoping to avoid gluing a bunch of crap to the motherboard.

Basically my knowledge gap, is if running a PWM to a relay on one side, and powering the TECs of the relay with the load power coming from a PSU is viable or will it just slam the relay open and closed too often/fast?

[Gray Mole]

My knowledge on pwm relays is a bit out of date, but the ones they use on the automotive power circuits like pwm fans should keep up.

I would recommend using pwm relays to the right amperage but TEC's can be pretty heavy. You can run parallel relays though. Solid state relays can be capable of that kind of fast switching.

http://www.trossenrobotics.com/store/p/5467-BattleSwitch-radio-controlled-10A-relay.aspx

Just a for instance, not sure if that's close to TEC load, but it's a pwm relay.

If you go to a Hobby Shop and ask about that (I mean the more techie ones, that sell replacement relays for pwm, or electronic shops that deal in that stuff like Radio Shack did/does)

But a lot of refrigeration controllers have pwm outs on them. If you use a relay that's capable of fast switching and has a decent lifespan to it (even 100k seems light for this kinda thing) then you may have some luck :)

Otherwise, maybe someone in the TEC forum has done a mod similar to this one.

Gray

[CrazyNutz]

I may have to use a chiller to reach my cooling goals so in an effort to avoid condensation but simplify the process I propose the following:

Speedfan reads my MB sensor (It's located down by my second PCIE slot, the coolest part of my case) and it is always a couple of degrees higher than ambient (usually about 2-5C higher than ambient). Speedfan can also control fans based upon a set temp sensor, as I am sure you all know. What I was wondering is if it is possible to use motherboard PWM function via speed fan, to a relay to provide power, then to a dual TEC chiller setup.

Through trial and error I could build a ramp for the PWM control in speedfan to keep the CPU within 5c of the MB temp sensor. I do understand that the water temp will be well below ambient at this point, so the need to insulate the tubing, reservoir, pump, fittings, and blocks will be there, but I am hoping to avoid gluing a bunch of crap to the motherboard.

Basically my knowledge gap, is if running a PWM to a relay on one side, and powering the TECs of the relay with the load power coming from a PSU is viable or will it just slam the relay open and closed too often/fast?


A relay would not be the thing to use here, it can't handle the switching frequency, also if you were to hook your PWM signal directly to a relay you would blow out that part of you mobo from back EMF.

The correct part to use would be a Mosfet capable of high current. You need to look up "pwm switching power regulation" on google, and understand how it works so you can build a circuit.
Typical circuits would use a Mosfet -> inductor -> capacitor.

[tcclaviger]

Thanks, time to start reading some books on how to properly create a robust circuit capable of controlling this stuff.