Introduction: Making/Upgrading Your USB Powerbank
In this instructables, I'm going to show you how to make your own power bank. I fitted it in a case of another (smaller) power bank, because it had the right size.
For the power bank we're going to make, we need a separate charger to charge the battery.
! Attention !
This project uses LiPo batteries. You need to be carefull with charging/decharging these batteries, because the can explode when not handled with care!
Lets get started!
Step 1: Changing the Little Power Bank
In the first step we're going to change the small power bank, so the 12V to 5V converter fits in.
First open up the power bank. The lit is held in place with clips. Just pry it open.
After that you need to remove the 1 cell battery with charge circuit. Now take a knife/dremel and make the hole in the front larger so 2 USB ports will fit in later. I also needed to remove some standoffs in the case itself.
Now the case is ready to be refitted!
Step 2: Electronics
For converting the 12V from the 3S lipo battery, I used this small usb converter because it fits in the case.
First I needed to remove the USB socket, because it was a little to high. I then added the socket again with some wire.
After that, I soldered some short wires to the battery connector. And screwed them in place.
Now It's time to make a hole for the battery plug in the back of the case. I used a drill to make a hole a little smaller than it should be and used a file to make it fit snugly.
It's time to insert the electronics in the case. I fitted them in and then used some hot glue to secure them in place.
That's it! Close the case and you are ready to go!
Step 3: Resume
Well, now you have a battery pack that can last at least 3 times longer than it could before. And it can charge your phone at 2A.
Small pack
3.7V - 2200mAh
> 8.14Wh = 29304 Joule
Big pack
11.1V - 2200mAh
> 24.42Wh = 87912 Joule
I hope you like it. If so please vote on it.
Laurens

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5 Comments
7 years ago
Hey,Can i use a powerbank 5v output via 12v converter to use as a li po battery for my four wheeler 300 rpm dc geared motor operational at 12v?
Reply 7 years ago
You can probably do that, but I don't recommend it, because the 5V powerbank probably can't supply enough current.
If you would like to do it that way, you'll need another type of converter. 5V to 12V boost converter.
Laurens
7 years ago
Laurens,
Your guide to build your own Power bank for mobiles is simple and clear even a beginner can build.
I stay in Bangalore, India where can I get the circuit for converting from 12V to 5V?
A. S. Bhasker Raj
Bangalore
India
Reply 7 years ago
go to amazon.in
http://www.amazon.in/Output-Converter-Step-Down-KI...
Reply 7 years ago
Thanks, I think Gearbest also ships to India.
http://www.gearbest.com/development-boards/pp_6933...
Otherwise any car cigarette plug usb charger should work (probably not at 2A)
Laurens