Last summer I made a solar charger(maybe I'll post some pictures), I used a 5v 320mA solar panel, 5V regulator and a USB port.
So now I can charge my cellphone and mp3-player through USB.
This works fine, but I would like to make an USB battery that I can charge and take with me..
Something like this http://www.dealextreme.com/p/rechargeable-usb-emergency-power-backup-pack-2400mah-3060
I have no clue on how to make this.
Can anyone help me with this ?
I have some li-poly batteries so I would only have to know wich electronics to use and how to solder them :)
The battery pack should be charged through USB and have and USB output :)
Thanks in advance,