Pelt: Sub-Ambient but not Sub-Zero

[Jim]

Hi Guys,

I want to stick a pelt back in my rig but cant be bothered with all the insulation malarkey. Therefore I want to know the best way to control a peltier, so I can tweak it's performance and keep my temps around ambient. Any idea's?

[Mr. Smith]

I'll get back to you on this one as I did something to mine and now performance is awful - idles about 1 deg and full load mid to high 20's...

I think I knocked it and it isn't seated properly, not really what you were looking for...

If you give the pelt less wattage then it doesn't perform as well, so this would give you your desired effect.

Perhaps a 'pot' on the X3 to turn down the power.

[Jim]

Originally Posted by name='Mr. Smith'

Perhaps a 'pot' on the X3 to turn down the power.

Ye thats what I was thinking, but I think it'd need to be something inside the PSU rather than a pot/resistor outside as it'd need to cope with 20a passing thru it

[Mr. Smith]

Hmmm, internally would be some huge resistor, or maybe ghetto mod a large potentiometer - isn't a dimmer switch essentially capable?

I know a sparky but I'd have to get him over and open up my booster to get any better ideas... I only did gcse electronics and that was 8 years ago lol

[dave1920]

This is something i've been wondering as well. If looks did not matter is it possible that contecting the pelt to a variable power supply, like this http://www.maplin.co.uk/Module.aspx?...upply&doy=29m7

would do the job. I appreciate that the pelt you are talking about may have different specs from the swiftech 6500 that I am looking at but is it possible?

Dave

[quietfreek]

XMS what power TEC are you looking to control ?

Are you looking to to apply the TEC directly to the IHS or are you looking to cool the liquid in a W/C loop to ambient as dell do in there H2C which is much more efficient as you arnt looking to pump the full TDP of the PROC through the TEC.

[Jim]

Originally Posted by name='quietfreek'

XMS what power TEC are you looking to control ?

Are you looking to to apply the TEC directly to the IHS or are you looking to cool the liquid in a W/C loop to ambient as dell do in there H2C which is much more efficient as you arnt looking to pump the full TDP of the PROC through the TEC.

Hi Quietfreek, It's a 320w pelt and at the moment it's cooling the CPU thru a Maze4-1 Pelt waterblock.

Any idea's on how to tone it down would be appreciated. Or maybe I should be looking at a lower wattage pelt - sommit like a 170w?

[quietfreek]

Holy thats a lot of juice

i would want to be building a PWM controller, do you have any experience in power electronics?

are you driveing this from your PC PSU ?

if you budget will allow id use something like the m-cubed tbalencer

http://www.t-balancer.com/english/bng.htm

use this to create a PWM signal with a custom profile based on ambient temp and proc. temp sensors. Id then input this into the base of what is esentially a power amplifer, a suitably spec'ed darlington driver / mosfet (s) that can cope with the current you need, As your not driving an inductive load the circuit would quite simple, with a little care and posably a couple of capacators to smoth the current draw from then power supply and delivery voltage you can have very low power loss control of you pelt / cpu temp tuneable in windows and microprocessor controled.

if your really interested ill pull out some of my old 3rd year electronic eng. notes and spec up some components / sugested circuit total cost shouldnt be too much.

[Mr. Smith]

Hey quietfreek,

XMS will be using the booster x3 300w psu for the pelt, a secondary psu. (we have the same pelt set up more or less).

p.s repped for your good suggestion.

[quietfreek]

Thats good its less critical that the current draw is ripple free if its off a 2nd PSU.

Does anyone have any contacts with M-Cubed i'd need to know the switching frequency of there PWM signal to spec the mosfets