DIY thermoelectric (peltier) laptop cooling (anyone done it?)

Discussion in 'MacBook Pro' started by Ploki, Jan 8, 2013.

  1. Ploki macrumors 68030

    Jan 21, 2008
    I haven't done it. I'm thinking of doing it though.

    Basically you create a macbook pro stand, with either whole surface of peltier elements or just the hottest areas. You put a small fan underneath the elements so you don't get too much heat on the bottom side...

    Could this actually benefit cooling versus commercial "big fan" designs?

    Basically you end up with a constantly cool laptop desk, it probably wouldn't consume that much power to get it to 15 or so degrees. I have a few at home and they get freezing cold.

    I have no idea what kind of impact would it have... 4cm*4cm elements are cheap, about 0.99c on eBay.
  2. jjj333 macrumors newbie

    Sep 21, 2013
    My Toshiba/Satellite L850 is a great little laptop with only one serious problem:
    Most of the time the cooling fan of my keeps on running at high speeds, indicating that its cooling system is poorly designed and its noise changes interfere with my audio recordings. Since I couldn't find a solution to the problem on the Internet (only same complains), I thought of helping myself.
    After some testing I discovered that if the TEC is put to work hard, it produces enormous amounts of heat, which requires a big heatsink, strong fan and so, makes them not really useful for PC cooling.

    Yet, the moment we find the point at which the TEC produces a useful amount of coldness and moderate amounts of heat, laptop cooling becomes a feasible option.

    For instance, I found this point to be, when I connect a (cheap China made) PS of 12VDC/1.25A to my TEC 12705.
    Result: On connection the load then drops the voltage to about 7V6 and rises the currant to 2A1, the heatsink gets slightly warm, its (12V nom.) fan is almost inaudible and the PS stays moderately warm. - Ideal!

    The cold side becomes finger-hurtingly cold; i.e. more than sufficient to help cooling down my laptop:
    With a Dremel Mini I sawed a hole around the laptop's cooling system. Onto its exposed copper cooling rails I spot-soldered a few Chilean 100 pesos copper coins to almost level the surface with the laptop's bottom cover.

    Under the wooden shelve board onto which my laptop is placed, I sawed a round hole and (spring) suspended the Pelt unit. Its cold part, consting of a 1/2" round, solid brass piece, is then made to touch the laptop's copper coins.
    The suspension of the TEC unit and a bit of thermal paste helps to level-adapt and transfer the coldness to the laptop's copper rails. The laptop's cooling fan then only serves as backup and becomes almost redundant and unemployed... like many of us. :)

    Yes, I agree that that there exist lots of contradictions on this idea...

    Well, it's not meant to replace the laptop's original cooling system; just complementing it !!
    That way the Toshiba's cooling system /fan works much less and runs quieter.

    At this low voltage condensation is not an issue. Besides, any condensation would drip down, back to the TEC; not upwards into the laptop.

    I'm just glad having found this effective solution and thought of sharing this idea with people seeking to overcome the same problem, in the hope they might be benefit from it and contribute to improve this idea with some even more innovative ideas...

    It's just working fine at the power supply I am using. Any more power will generate too much heat and more coldness I do not need to help the laptop cooling down its copper cooling rails.
    That's why I do not have the condensation problems either.
    I also learned on thing:
    There are lots of sceptical opinions about it on the Internet, but finally one has to gain one's own experience with it than just rely on other people's opinions.
    Result: my laptop definitely benefits from it, because I know all too well how its cooling fan was whining at high speeds, before the TEC addition...
    So, I really do not believe in doomsday warnings anymore. :)
    The great thing is the Toshiba fan and cooling system is left in original condition and serves as a TEC efficiency indicator and as a back up, should the TEC fail to deliver.
    Besides, I insulated the TEC's hot side from its cold side with a thin layer of Styrofoam. Yet, since the hot side has a huge heatsink, its fan is almost unnecessary. So, I reduce the TEC's heatsink's fan with a 40 Ohm resistor. That reduced its noise to almost "0" and at the same time giving the TEC a bit more juice...

    In case something goes wrong Toshiba's cooling fan will let me know by running faster at higher speeds... like it used to run without the TEC' help.

    I am practical man: once something proves to be working, that's all I need to accept it as logically correct and progress!
    Hence, I successfully applied it on my Toshiba Satellite L850.
    From my observations I take, that the CPU triggers the laptop's cooling fan. This fan has about 5 velocity stages and according to the data processing demands, the fan adjusts its speed.
    Yet, since the TEC keeps the laptop's cooling copper rails cool, the fan only runs for about 1 to 2 Sec at the second velocity stage and then turns off.
    Before, without the TEC, the laptop's fan was running at much higher speeds for long periods of time; often for hours.

    Also, when I turn the TEC unit off, the laptop's copper rails heat up the normally ice-cold 1/2" round, solid brass piece from the TEC unit gets warm!
    If that isn't enough proof for success... I don't know what is!
  3. xxcysxx macrumors 6502

    Oct 12, 2011
    I thought it would require more energy to cool the peltier device than it is to cool the cpu itself. for what it benefits, it cost considerably more in return.
    it's no wonder why many enthusiast don't consider peltier and opt for the much clunkier water cooling setup and the all mighty powerful phase change cooling.
  4. jjj333, Sep 21, 2013
    Last edited: Sep 21, 2013

    jjj333 macrumors newbie

    Sep 21, 2013
    I discovered the contrary... because as mentioned my TEC 12705 runs on a powers supply of only 12V/1A25, which on load drops to 7V6/2A1, yet the result is amazing. It's because I channel the coldness directly to the laptops copper rails. That way it's pretty effective. My TEC unit cost me less than $15
    Cost comparisons:
    Phase change cooling costs about $1000+
    Water cooling is expensive,too.
    The cheapest solution then is to mount the hot PC into a 2nd hand bar fridge... :)

    Of course, to cool down a PC would need far more cold power and that renders the TEC impractical.
    So, I'm glad having discovered a loophole! :)
  5. zipur macrumors 6502a


    Mar 3, 2011
    The great state of Texas

    Pretty cheep already here on Ebay $14 usd.

  6. jjj333 macrumors newbie

    Sep 21, 2013
    Yes, I thought of that, too. That might help somewhat, but only if you expose the laptop's cooling system. Otherwise it just serves to dust off the bottom part of your laptop. :)
    My TEC laptop cooler cost about the same!
  7. Astroboy907 macrumors 65816


    May 6, 2012
    Spaceball One
  8. jjj333 macrumors newbie

    Sep 21, 2013
    No, that's not possible, because the cold part of the Peltier is too close to the hot part, unless one would channel the hot air through a pipe or hose under the table.
    Even that would still be impractical, because to produce sufficient cold air the Peltier would need to run on much higher power (12V at 3or 4A) and that would generate masses of heat... and require a tube/ hose out of the window.
    Forget it!

    My Peltier laptop cooler is only effective, because I touch-connected the coldness directly to the laptops copper rails.
  9. The Unseen macrumors member

    The Unseen

    Jun 24, 2012
    Naples, Italy
    I am thinking at something like this for weeks. I've ordered on Amazon a small Peltier cell (it will arrive tuesday), and I want to insert it in my little DIY aluminium stand that now hosts a 12v, 8 cm fan. I've seen some examples on heavy modded PCs, and the result is not bad. Obviously I have to put it in a heat sink with fan on the hot side, or the JJJ333 solution, the resistor if possible.
    The only thing that concerns me is the Dew point, so i have to study the table and I have to read the temperatures on the bottom plate of my MBP 15'' Late 2011 to avoid this.
    In the next days I will publish the results
  10. jjj333 macrumors newbie

    Sep 21, 2013
    I must admit, I didn't get it right the first time either. Initially, I thought of just pumping the TEC's cold sink air through a thermally insulated hose... but I soon discovered that this would require a far stronger power supply and that's where I got into all sorts of problems, such as excessive fan noise, excessive power requirements and condensation problems.
    Well, you too will find out! Happly engineering!
    Here the Chinese sell complete TEC units for only $18 incl. shipping:
  11. The Unseen macrumors member

    The Unseen

    Jun 24, 2012
    Naples, Italy
    Thanks for the link :)
    I already have a heatsink, I need only the cell, and when the cell will be shipped I will try to find a comfortable solution. I love DIY things!
  12. jjj333 macrumors newbie

    Sep 21, 2013
    I am a DIY doer as well, but be careful... in case you want to do the same as I did, i.e. unscrewing the laptops copper rails and solder copper coins etc. to it in order to raise its level, don't forget to trace and mark previous arrangement of the laptop's rail and its fasteners.

    So, before any soldering, place the laptop/s cooling rails onto a piece of wood and trace its rails and then hammer nails into its fasteners, as to maintain its position.
    Otherwise it can easily happen that during soldering the position of the rail fasteners move and you will have the chore of reheating and re-adjustment over and over again, until you regain its original position.
  13. The Unseen macrumors member

    The Unseen

    Jun 24, 2012
    Naples, Italy
    I am not applying this solution to internal components, but only on the bottom plate of the MacBook Pro. I've noticed that a good ventilation of the plate (in addition to the reapplication of the thermal paste) is enough to stay cool and with low RPM of the internal fans, I am going to try the Peltier Cell to stay silent too.
  14. jjj333 macrumors newbie

    Sep 21, 2013
    Some laptops, like my Toshiba Satellite L850, allows you to adjust the Min & Max processor state. That way the CPU won't overwork and cooling kept to minimum.
    I adjusted mine to 80% and with the help of the TEC the cooling fans are virtually inaudible. That's the way to go! :)
  15. The Unseen macrumors member

    The Unseen

    Jun 24, 2012
    Naples, Italy
    I would like to use all the power of my Mac, today i will receive the TEC and I will make some experiments, I hope it will be effective :)

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