172W Peltier...

[koei]

Bought this 172W 40x40 TEC from DD few weeks ago. Was trying to use it for my X800XL and strange thing is, it barely goes negative. At first I though it wasn't making good contact with core, but after taking everything apart and taking the TEC out. I tried camping hot side to the water block and measure cold side temp with loop running. The TEC is 24v and I am running it at 15.5v or so. The best I could get the TEC to go is close to 0C or so. Am I missing something? I tried using a 95W 15v TEC I had, thats partially cracked and it ran fine and got to -7C or so.

[n00b 0f l337]

1) Are you giving it enough amps, are you able to?
2) Do you have a cold plate for the cold side?


I tried camping hot side to the water block and measure cold side temp with loop running.

camping?

[koei]

Theres more than enough amp in this PSU, about 60A, and yes, I have a cold plate.

[n00b 0f l337]

How hard do you have the tec clamped?

[dward3]

koei,
How are you cooling the TECs? Try giving it less volts.. Then your temps will come down :)

Post some pics if possible :slobber:

[koei]

The TEC is more than sufficiently cooled. It's on a Maze4 GPU going to a dual heatercore and theres nothing else in the loop.

[n00b 0f l337]

Sounds like a broken tec maybe?

[ls7corvete]

Too little volts I think. There is software and also some equations that you can use to find dT at different voltages.

[rhino56]

isnt that a 24v tec?

[n00b 0f l337]

Schwing we have a winner. Forgot about that. Its a 24 volt tec! DUH!

Yeah, its a 24 checked with DD. Your giving it 15.5 volts, so its sucking 4.6 amps... Your running like 71 watts of tec power. No wonder why...

[koei]

Hmm... Strange, I was under the impression it would be more than 80W with just 12V.

[n00b 0f l337]

Nope. Cause when you start decreasing volts, it starts decreasing the amp taken as well. So your giving it definetly not enough.

[STEvil]

they become more efficient as you decrease power also, though.

I'd say about 80-86w maybe... just enough to hold an X800XL around 0-10c maybe or so.

[ls7corvete]

they become more efficient as you decrease power also, though.

I'd say about 80-86w maybe... just enough to hold an X800XL around 0-10c maybe or so.

4-5a at 15v to get 0c, sounds good to me, and even more encouragement to continue with my current project. :toast:

[dward3]

Here's my 80w pelt on 12v while cleaning the tubes with some orange windex. :)
http://img297.echo.cx/img297/4103/dscf00382db.jpg

Temps around -11.4˚ :
http://img297.echo.cx/img297/2228/dscf00402zr.jpg

Temps @ -15.1˚ :
http://img297.echo.cx/img297/6321/dscf00421iu.jpg

Edit: Resized Images

[rhino56]

thats a nice thermometer.
you can clean the insides of your tubing with dental floss and a piece of rag.
tie one end if the dental floss onto a small washer and feed it thru, then pull the rag thru a few time with some soap or something on it.
ive done that before to get the residue off and it worked pretty good.

[dward3]

Thanks for tip on the cleaning method Rhino. You'll see a DT-200 on ebay once in awhile for pretty cheap. :)

[rhino56]

i just got this one
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7525340688

[HiJon89]

Well according to the specs at DD where he bought it, its 172W @ 24.6V, so at 15.5V it should be (15.5*172)/24.6 which equals a little over 108W, so theoretically the temps should be better than with the 95W 15V TEC so I'm not sure whats going on.

[ls7corvete]

Well according to the specs at DD where he bought it, its 172W @ 24.6V, so at 15.5V it should be (15.5*172)/24.6 which equals a little over 108W, so theoretically the temps should be better than with the 95W 15V TEC so I'm not sure whats going on.

Like I said, dT and the amount of heat that can be pumped change with voltage. I dont think the amperage changes linearly either.....

Not my project so I will let you guys look into it....