Picture of $5 Mini USB Fridge!

Now that we're seeing those 12 volt camper coolers turning up at garage sales and thrift stores (I found one for $2.50), here's a neat little idea for turning it into a customizable mini-fridge powered by a USB port!
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Step 1: Taking out the Peltier/Heatsink Unit

Picture of Taking out the Peltier/Heatsink Unit
You'll basically just need a phillips head screwdriver and thin socket or needlenose pliers to take apart the heatsink and fans, which will allow you to remove the unit from the cooler. Now, you might ask why you'd want to do this and not just use the cooler. The answer is because most of the time when you find one of these the case will be cracked and the cord is missing, but that's not a problem...

Step 2: The Peltier unit and Clean Up

Picture of The Peltier unit and Clean Up
Sandwiched in between the heatsinks, you'll find the Peltier unit, which loks about the same size and thickness as a computer CPU. In between the top and bottom layer, you'll see the special substrates that have the unique properties that make the Peltier unit cool on one side while heating the other when an electrical current is applied. There will, in some cases, be spray foam insulation in between the two heatsinks, which is very easily broken away with just your fingers. You can safely remove the peltier unit from the other heatsink, as it will be held only by thermal compound. Once you've cleaned up the top and bottom heatsinks, place the peltier back in between the two heatsinks and retighten the bolts. If you have any thermal paste left over from putting together your own PC, you can optionally clean the old paste away and reapply new paste to each heatsink just as you would on a CPU heatsink/fan assembly before attaching it to a CPU.
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poncos28 days ago

what kind peltier that i can use ? can i use peltier 12 V 6A to usb ? or i have to use peltier 5V 1A ? thanks :)

jellejelle222 months ago
Is there any other material i could use for building the fridge?
jellejelle222 months ago
Is there any other material i could use for building the fridge?
nic.bryan.733 months ago

It seems like this could be adapted for a large water bottle as well (for example, I have a 1Gal bottle that I use for everything. Sealing the 'cool' heat-sink to the inside of the bottle would be good for keeping your water cool.

kamhagh5 months ago

my peltier is 4amps and its the only thing i can find, at 5 v its aroun 9 amps , what can i do?!

+ the other side gets 0 degrees when connected to an old computer psu !! but i don't know how i can make drink cold with it, placing drink on top of it does nothing ! also connecting a heatsink only makes the heatsink cold, not the air :|

johny.xpress7 months ago

i wanna buy it.please inform site is <a href="">白ロム 買取</a>

Ravirar1 year ago

wow this is cheaper than the USB soda can mini fridge on ThinkGeek

Schmidty162 years ago
ok could this be converted to make an ac very good job!!
ilpug2 years ago
I wonder if the same USB fridge unit could be hacked into an Xbox to cool it down....
Itscrafty ilpug2 years ago
Wouldnt that possibly create condensation?
ilpug Itscrafty2 years ago
Not that I know of.
Itscrafty ilpug2 years ago
K, just wondering.
Should be, put in a fuse, or somesuch to make sure that you dont suck too much power
Great job! Very neatly done with good documentation. Just a note. Now they are selling $5 mini fridges on ebay that hold a soda can. I would recomend using it's unit as it is meant to run off of a 5v usb port, and it has a fan built into it. All you would have to do is make a "cooler" looking case for it. :p
Langarulz3 years ago
wouldn't it be better to put the heat sink at the top of the cooler?
no because it becomes less effective if not in contact with the bottle itself, another reason why cans get colder faster.
Hey guys. I'm planning to make this for my science project and I was wondering if anyone can explain some parts...

1.) where can I buy a cheap peltier cooling unit? or the 12V camper cooler (coz I really can't get how you stick that to the unit... explain please? sorry. I'm such a rookie...)

2.) how to make the fridge light up when you open it? (which is better lights when closed doors or lights when you open the door? please explain how to do this too)

3.) can this fridge be cool enough that the can (or bottle) be cold enough to drink lets say if you place a room temperature can inside? and can it be cool enough in less than 5 hours? (I read your comments to get insights)

Please help guys.... Thanks in advance! ♥♥♥
rab2363 years ago
Wouldn't it be more effective if the cooler was on the top, so it would cool all hot air rising up?
If I were making this fridge, I would put the heatsinks at the top...cold air falls, hot air rises. I would think it would be more effective.
for such a small area it will most likely make no difference
yep. but if you touch the top you'll burn yourself... lol
Lew8 red-king6 years ago
use a low noise fan? lol
ctm53 Lew86 years ago
you should add the heatsink on the side and stick a fan on it
keep in mind the current drain

5V is fine for powering a fan (well duh you can get USB powered fans comercially). I am not sure how much current a USB port can handle.

Too be safe I would buy a cheap USB Hub with its own power supply and power the "fridge" off of that. It may or may not be as reliable but since it is powered off the hubs power supply you won't fry the power on your computers usb. I have two notebooks that have fried power on their usb ports (data connectivity still works but you need external power on the device, such as a hub).

For temp control couldn't you build a switch with some resistors to regular the current going into the module? Also, for a desktop hack perhaps you could wire the module directly to the power supply on the computer by routing the cable through an expansion slot. Of coarse with that you might get two effects. Firstly you might end up with a freezer rather than a fridge, and two the heatsink will could get extreamly hot. In that case you would def need some additional cooling.

Thanks for this instructable it has given me some ideas. Such as building a custom case (perhaps using styrofoam as an insulator) and a brand new module. Such as this one
please say you haven't bought that module yet? if you've got the time to build your own custom case (I know i haven't) buy a peltier from virtual! ive got a 400watt one on its way that only cost 12 pounds! i'm guessing that if you want to make your own custom case your either a keen gamer or just want external power from the psu? if you just want external power from your psu you could adapt a spare pci slot on the case to be a dc power outlet? btw the max current that can be drawn from a usb is 100ma without request (there's no way to request 500ma other than through hardware, so don't even go there.
with a unit like that do you think i could make an actaul minifridge, like 2 by 3 size, hooked up to a socket of course, and any cheap but affective insulations i can use, was thinking foam baord on the outside with a wood frame and more foam board with insulation inbetween that.
thanks for the link/info, no I havn't bought any of the parts yet, I just tought this project up as soon as I found this instructable, currently I have a limited budget and upgrading my harddrive is a bigger priority sorta a keen gamer, but mosty just like building electronics wanna get my advanced amateur radio licence so I can tinker with transmitters *evil grin*
that's why there's a heatsink
what i would do is make another fridge on the other side of the heatsink which wouldn't really be a fridge but a toaster(kinda) that way hot air goes up cold air goes down.
 but there is a fixed temperature differential with a peltier unit... if you capture the heat of the other side then it will heat up as will the cool side so that wont work... unfourtunatly, cool idea tho
 im making a project for geometry like this... im making a usb mini fridge out of a great rhombicuboctahedron 3d solid and since i feared it wasnt going to be cold enough i was going to do exactly that!
polar bear63 years ago
your favorite site is metacafe? even after they removed the kates playground movies? wtf man
gmackenzie3 years ago
Would i be able to do this but in a wooden drawer ?
Why is playstation and xbox a tag?
every videogame console these days has usb ports on them.. ill let you figure out the rest ;-)
however, video game consoles require 110V and the 5V offered by a USB port isn´t enough. Also, would you be able to hook up your tv to the USB as well? it´s not very practical, but if you have other ideas please shoot :)
Well, the figure it out yourself comment didn't work, so. Plug the mini fridge, into the USB port on your console. Didn't think the obvious needed pointing out, but then again, I've been wrong before.
ionic3 years ago
Cool design!
Just a thought on efficiency. Since heat rises and cool air draws downwards, wouldn't it have been more efficient if you places the peltier device on top where the heat would flow up and away from the cooler surface and the cold side would coll downwards onto the bottle of water?? Basically a similar concept as placing your icepack on top of the goods you want to keep cool in a cooler.
norton2203 years ago
WOW! that's probably one of the coolest ideas i've seen in a while! i cant wait to find an old cooler and make one myself, so awesome. Good job and great attention to detail bro, keep up the good work!!
This is truly AWSOME! I love mini fridges and they are even better if they can run off 5v!
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