This might be better suited for the mobile section of this forum.
They make portable battery chargers with interchangeable tips. Mine does micro, mini, USB, samsung, and iphone. It has a ~5000mAh battery which after losses is good for about 2 full phone charges. It recharges through the same USB cable, which you can then plug into a wall or car charger. Just charge it up every night. Mine has two ports for simultaneous charging, but only comes with one cable.
USB 2.0 is not bad for devices, but is much slower, I believe. Should not affect your device.
__________________
San Francisco: Asrock Z87E-ITX | Intel i7-4770k | 16 GB DDR3 @ 1866 | XFX 7970 @ 1040/1500
Honolulu: Gigabyte MA790X-UD4P | AMD Phenom II X4 955 @ 3.8ghz | 8GB DDR2 800 | Sapphire HD4890
London: ASRock 4CoreDual-VSTA | Intel Dual Core E7400 @ 3.1ghz | 2GB DDR2 667 | ATi X850 XT @ 540/590
|