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Making a mini-fridge for my locker? Answered

I am trying to build a fridge for a my locker at school to keep my drinks cold. I am going to construct it using the method in "$5 Mini USB Fridge!", but since it's in a locker I obviously can't use USB power. I thought about powering it with a 9V, but I don't know if that will last very long. Any ideas on how I could power it?



take a couple 9volt car battery packs and wier em to together and theyre you go

USB outputs about 5-6 volts. you could get a 6v lantern battery, or you could build a battery pack with D cells, C cells, or even AAs or AAAs.
Whatever way you do it, plan on spending a fortune on batteries.

Honestly, I know where you're coming from: "It'd be really cool to have a mini fridge in my locker!" Fact of the matter is, fridges use a sizable amount of electricity, enough to drain most batteries in a few hours, if that. If you don't want to be replacing batteries all the time, you'd need a VERY large battery. It's much simpler, cheaper, easier, and more environmentally friendly to just use an ice pack or a cooler.

It would be a lot simpler just to bring ice-blocks in from home every few days, or, if you want to be REALLY clever, little tanks of frozen proplylene glycol. Of course, you'll need good insulation, but polyurethane foam is about the best you can get.


That what I mean by ice-blocks. Packs is a better word.

I visualised blocks of Ice slowly melting and flooding the lockers!

We once had a pupil who brought in a plastic bag full of maggots so he could go fishing after school (he said) Unfortunately they got loose and spread everywhere - For a while it was mayhem - I couldn't believe so many teenagers were scared of Maggots.


5 years ago

I would use AA or AAA rechargeable batteries, unless you have a source for real cheap/free 9 volt batteries. Even then, I'm not so sure a 9 volt battery would last a full day.

Depending on the manufacturer, some would not even cool the soda or
other concoction that surely is against the school rules.

Why would having a small fridge be against school rules?

Never said the fridge is against the rules.
( it will be after you are discovered and you will be ).

I did say that what you put into the fridge
{ unless it is only water } is against the rules.


Oh, ok. Gotcha. I was planning on using it for my Coke Zero bottles (which are allowed at school because I usually take them, only there are warm by the time we have break).

I don't know about fridges , but I do know that a 12 ounce aluminum can will fit inside a one quart stainless steel Stanley thermos. Maybe you could get two cans
into a 2--quart thermos. It's a pretty close fit and if the cans expand a bit
from being shaken ,you might not be able to get them out.
Just to be on the safe side , it would probably be best to tie a string to the pop top
so you could open the pop top just a bit to relieve pressure and then pull the can out with the string.
I have never tried it , since I don't drink carbonated stuff.
Just chill a can of coke and put the can in the thermos.


5 years ago

USB can deliver an amp of current and the ible you refer to
points out it was using 1 amp at 7.5 VDC.

A 9 Volt battery cannot deliver the power you need !

The 6 Volt lantern battery suggested by Re-design is your best bet.


Use a 6 volt lantern battery. You can probably use it without any reducing and it'll last a lot longer then even a hand full of 9 volts.

You can power the USB fridge with a 9V battery but you will need to use a 5V regulator to do it. You'll loose a good bit of power in the transition from 9V to 5V and a single 9V battery won't last very long. You'll want to have several 9V batteries wired in Parallel to increase run time or use a larger battery. A good sized 12V sealed lead acid battery would probably be your best bet.