At JohnFen, re: USB power.
There is a dongle called a "USB condom" that allows you to plug in any standard data+power USB cable in while the other side of the dongle only has the power connections. I've got one on my keyring so I can charge stuff in public places & not worry about where the USB port has been. It's less expensive & more convenient than a specific power only USB cable, you only need carry the single normal cable, as long as you remember to wrap your plug before you get a charge out of it. ;-D