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!

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...
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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.
yep. but if you touch the top you'll burn yourself... lol
Lew8 red-king8 years ago
use a low noise fan? lol
ctm53 Lew88 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 http://store.qkits.com/moreinfo.cfm/QK66

Here is the updated link for the peltier module:


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 village.com! 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
for such a small area it will most likely make no difference
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!
JoshH12911 months ago

Another thing I thought I might add is, you can help the cooling heatsink by polishing it to an almost mirrored finish, it should transfer the cold way better then. I'm not sure on that, but it makes sense to me.

Heres my logic, If you take a mirror finish polished aluminum, brass, or copper heatsink and put it in the freezer you won't find that it has frost on it after 24 hours. But, put the same kind of heatsink that has been scuffed up slightly in the freezer for the same amount of time and 9 times out of 10 where the scuff marks are you will find frost, maybe even a thick layer of frost.

Just kind of thinking out loud, but hopefully it helps.

BTW Chocolate from a Hershey's candybar works pretty good to polish aluminum that isn't too pitted..

Just to interject quickly before someone takes this advice: The effect is actually the other way around. Highly polished surfaces reflect heat more effectively, and thus don't work quite as well for heat transfer. I doubt in this case it would make much difference, but it would be less effective for it to be shiny.

JoshH12911 months ago

ok not sure if anyone has thought of this, but if you have a peltier that runs on 5-12 volts you could always use two seperate USB cords and attach them both to a single peltier... This would more than likely allow you to use just one Usb at 5 volts, or use both Usb's at around 10 volts. I would imagine doing it this way would almost double your cooling effect inside, but I can guarantee you that a larger heatsink with a fan would also be needed on the heat side. On the outside to get rid of the heat more efficiently it might also be a good idea to try and incorporate some sort of a heatpipe, kind of like inside a laptop for the CPU cooler... these are just a couple of thoughts that might help if someone wanted to actually figure out how to make a way more efficient version. BTW I loved the way this information was put together, I don't think I could have done it any better myself. Keep up the creativity!

JesseL351 year ago
It would be better if you added batteries to make it portable
Schmidty164 years ago
ok could this be converted to make an ac very good job!!


so just a thought but because colder air sinks wouldn't it be better to just put the peltier on top and make a wide base, then you wouldn't have to worry about your installation of the peltier and heat sink as much, what i mean by that is the holes around it that let the cold out.

poncos2 years 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 :)

Is there any other material i could use for building the fridge?

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.

kamhagh2 years 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 :|

Ravirar3 years ago

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

ilpug5 years ago
I wonder if the same USB fridge unit could be hacked into an Xbox to cool it down....
Itscrafty ilpug5 years ago
Wouldnt that possibly create condensation?
ilpug Itscrafty5 years ago
Not that I know of.
Itscrafty ilpug5 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
Langarulz5 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! ♥♥♥
rab2365 years ago
Wouldn't it be more effective if the cooler was on the top, so it would cool all hot air rising up?
polar bear65 years ago
your favorite site is metacafe? even after they removed the kates playground movies? wtf man
gmackenzie5 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 ;-)
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