Peltier-based Smartphone Cooler




Introduction: Peltier-based Smartphone Cooler

About: All about electronics!

Hi, there. Welcome back!

In recent years, smartphone technology has advanced exponentially, packing so much power in very tiny footprint that leads to one problem, excessive heat. Physical limitation on a smartphone limits the maximum heat that can be dissipated efficiently, which is on the low side compared to other devices. I sometimes play video games on my phone, which are resource hungry. My phone then gets too hot, which makes gameplay laggy. Also, my hand gets sweaty which double the trouble! Luckily, such product does exist on the market such as that smartphone cooling pad which even includes 5V output for your device! Also, there are many DIYs projects showing how to make one yourself! But, I wasn't satisfied enough. It's just a fan, what's so fun about that? I want something different, something fancy, something that probably has never done before. An ultimate peltier cooled smartphone!

Step 1: The Materials and Tools

Main materials:

  • 1X 12703 12V 3A 30*30mm thermoelectric cooler module
  • 1X Small heatsink with 12V fan
  • 1X Tripod phone holder
  • 1X 45*50mm 1mm thick aluminium sheet
  • 1X 45*50mm 1mm silicone thermal pad
  • 2X generic 3A switching step-down converter
  • 1X DC jack


  • Heatshrinks
  • Solder
  • Thermal glue (not thermal paste)
  • Wires
  • Double-sided tape
  • CA glue


  • Soldering iron
  • Unused card
  • Scissors
  • Flat head screwdriver
  • File

Step 2: Fixing Peltier With Thermal Glue

First, apply a thin layer of thermal glue evenly and place the peltier module on top. Apply a bit of pressure to make sure good contact between the heatsink and the peltier module. Don't rush it, wait until the glue sets.

Step 3: Modifying the Holder

The grooves on the inner part of the holder have to go in order to fit the peltier module. Use a file to file the groove flush.

Step 4: Fixing the Holder to the Heatsink

Sand both side of the surface that will touch each other and put just enough CA glue to the surface and press hardly to ensure good contact.

Step 5: Fixing the Aluminium Plate to the Peltier

Apply a thin layer of thermal glue to the peltier evenly. Place the aluminium plate on top and press it just enough to make sure good contact between the peltier and the plate.

Step 6: Soldering the 3A Stepdown #1

Set the output of the converter to 5V first before soldering anything else. Stick the stepdown with double-sided tape. Beware of the conductive heatsink below. Solder the output of the module to the peltier according to the polarity.

Step 7: Soldering the 3A Stepdown #2

Set the output to 13V first. Solder the output of the module to the fan.

Step 8: Wiring the Input

Connect both stepdowns on parallel with some wires. Put DC connector on the other end. Zip tie the wire so it won''t stress the solder joint.

Step 9: Add Thermal Pad

Last, put the thermal pad to the aluminium plate and done! You can apply some thermal glue beforehand for more permanent solution but I like mine to be removable. The thermal pad really helps with the heat transfer. You can tweak the two stepdowns to get the maximum cooling power with minimum noise. Mine happens to have the peltier on 8V and fan on 13.5V due to the power of the peltier used here.

Step 10: Afterthought

My peltier phone cooler does work very well, probably too well. The peltier I used here (12V 3A) is actually too powerful for this application. Even at 8V, the cooling power is enough to make my phone condense within minutes. I'd suggest using another peltier module such as TES1-4903 5V 3A peltier module with smaller heatsink. Don't let the size fool you like it did to me, they still pack enough power to cool down your phone. I'm going to make another one based on this 5V peltier and I'll do an update on it.

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    10 Discussions


    3 months ago

    Recently Black Shark (company owned by Xiaomi) came up with a similar cooler design for their phone (I guess they saw your article lol). And like you said in the afterthoughts, they built a smaller version, but aparently it's enough to get below 0°C (when it isn't attached to anything)


    Question 5 months ago on Introduction

    What should be incorporated inorder to Bluetooth control the cooling??


    Question 2 years ago

    As I've never used a peltier unit I'm a bit confused by this build, in particular the wiring. As I understand it the peltier produces a current created by the difference in temperature from either side. if that is the case, why the need for external power, could the peltier not power the fan directly, and in doing so the temperature would regulate the speed of the fan, so if the phone heats up, the fan goes faster? For that matter if the peltier is not powering the fan, what is its purpose? Is it just used as a sensor to control the fan, which is powered externally?? Genuine question


    Answer 2 years ago

    Peltier units actually have two modes. One is the mode you mentioned, creating power from a temperature differential, but they can also work opposite to that. That is, they can create a temperature differential if power is supplied to them. This is the way the author is using it. When he supplies the 12V power to the unit, it pulls heat from the smartphone side and pushes it to the heatsink side, cooling the smartphone in the process. The heatsink and fan are used to effectively dissipate the heat drawn out of the smartphone. Hope this makes sense.


    Reply 1 year ago

    Sure a simple heatsink will do the job fine, but where's the fun then? Your concept, the thermoelectric generator type, will also do the job and it's much more practical but my original plan was to make a phone cooler that actually cool down the phone, not just bring it close to the surrounding temperature. Besides, I live in tropical region where the air temp is constant at 30+ degrees, the temp difference between the hot side and the cold side won't be that much. Also, I just finished making the smaller, more practical version and it's so much better!



    Answer 2 years ago

    Right on point Josh! Peltier modules can convert electricity to temperature difference and vice versa. In fact, a specially made peltier for generating electricity does exist and known as thermoelectric generator (TEG) as opposed to thermoelectric cooler (TEC)


    2 years ago

    simply,use a 9 volt at the same time for fan and peltier module with 2 A output....
    is enough for "refreshing" a smartphone,not need a step down module(2) and save energy.
    Peltier module use many energy (70% is lost) must have economy usage of energy input and not inverse processing....this is a politic of usage about peltier module and if you add a secont module face at the first,on hot surface,you can rescue some energy....and performing the fan...or a led....see my instructable


    Reply 2 years ago

    9V is way too much for my peltier and way too low for my fan. Had to overdrive the fan at 13.5V in order to keep the hot side as cool as possible to maintain the best efficiency. While it's true that peltiers convert 2/3 of the power to heat, I don't have any better, suitable alternative right now with current technology. Honestly, I don't get what you're saying, maybe a little but mostly, no.

    Would be nice to tell me which Instructables you were referring. You got many Instructables there.


    Reply 1 year ago

    This link might be useful for you.(With some slight modification to the design) Modify it with a bigger heatsink, remove some parts of the fins on the heatsink so the peltier can be attached on the same side as the fins.
    The fan will cool down one side of the peltier with the airflow and also remove heat from the larger heatsink.
    Works on the same principle as a "powerless" stove fan.
    The cooler will become a bit more mobile without the external powersource.