USB powered cold lunch box!!!!
The problem I have with my lunch box is that the only items that stay cold, are those items that are inches from my ice pack… who likes warm Diet Coke at work……..? NOT ME!!!
So here is my fix.
Step 1: How i did it
For this I used a cooling fan and scrap sheet metal from an audio receiver.
You don’t have to use the metal plate like I did, I just wanted to have good surface to mount the fan and to hold the ice packs without sagging.
The USB provides around 5 volts (red and black wire). And it’s just enough to keep cold air circulating around the inside of the lunch box
Step 2: Mobile Power
I added a USB port in to an 18 Volt battery pack, but i didn’t use all the cells so it’s only 10 volts to the plug. That little fan might burn up with 18 volts...?
Step 4: Lunch Box R&D
This new one is not USB powered, I used a bigger 12 volt fan to achieve more air flow. The power source Is a wall adaptor that I had, it has a 12 volt 2 amp output. This is a more compact system.