Building an USB powerwall

Details
Category: In Progress
Published on Saturday, 28 December 2013 10:00

http://blog.curioussystem.com/2010/08/the-dirty-truth-about-usb-device-charging/

uses voltage division. resistors ordered from china.

 http://www.instructables.com/id/yet-another-iPhone-charger/

http://timothyb.net/DIY_iPad_2_USB_Charger.html

Apple charge configurations
D+ D- Power
2.0V 2.0V 500 mA
2.0 2.8 1000 mA
2.8 2.0 2000 mA