Saw this USB Battery Pack on trademe.co.nz a local auction site and decided to give it a try. Using 4xAA batteries it will supply power to charge and run almost any electronic device that draws power from a USB port.



Dimensions:
- 70mm Wide
- 80mm Long
- 20mm Thick

Features:
- Portable USB battery power supply for any device that just uses the USB port for power
- Power On/Off Switch
- LED indicator
- Pocket Sized
- Input Voltage: Four AA batteries (not included)
- Voltage: +5V
- USB connector


The only thing I did not like about it first off was the fact that the usb socket placement was on the front making the cable and connector stick out at 90 degrees to the powerpack. After popping it open to inspect the internals I found it a simple task to attach the circuit board to the battery pack with double sided tape and the whole thing fitted snuggly into the zip case that my Griffin EarThump earphones came in making everything a bit more Feng-Shui




The player I tested it on has a 400mAh rated battery and generally delivers between 10 and 11 hours continuous music play with an LCD off setting of 10sec and volume set at 15. Starting with the player having a full charge I managed to get 5 more full charges out of the battery pack giving me over 60 hours of continuous playtime from 4 "Energizer e" AA baterries.





All up this is a great little device and offers a practical solution for extending your players running time on a day to day basis or while travelling. At a mere $18.00 (NZD) including delivery I rate it as a must have bargain.

For those with the desire you can even build youself such a battery pack with only a few easily sourced components and a tin of mints. you will find a step by step guide HERE

Nice little gadget! Actually i was embarking on a small project from instructables.com using the 9V battery as source. Have got all the components, but currently lacking a female usb socket. My local electronics sold every component i needed except the usb socket. Guess i'll look around for some cheap usb hub where i can remove the socket to use it.
Will post a thread if i do manage to get 1 working, provided i find a usb socket.

But this USB Battery Pack, is a definite must-buy this christmas!

lattesurf, I was toying with the idea of making one when I saw this. A few of the web pages I found that showed how to build them claimed that the AA versions returned 2.5 times more power than the 9V versions.

Someone had also posted a comment that you should not try to board a plane with your homemade battery pack as it could cause you long delays and get you a cavity search
Sounds like good advice to me.

Glad to see that your exams are over, time for some R&R
Has your new player arrived?

tadad1 , yeap the 9V battery circuits are wasting almost half of its power on heat as the circuit mainly uses the LM7805, directly steps the 9V down to 5V, and 4V goes out as heat through the sinks.
The other AA battery circuits uses boost converters, very efficient, but you'll need a pcb of some sorts due to many components.

Guess the security might think that they are homemade bombs.. haha

Hopefully the player arrives soon, today's the 5th day of postage. So i'll expect it somewhere today to the end of the week for it to arrive.

lattesurf, DHL took 5 days to get to me so expect it soon