For reliable backup power, I have used the APC Mobile power pack, for Ipod, Phone and other items that use usb and micro usb connections.. As far as charging, nothing beats having electricity to charge all your items..
http://www.apc.com/resource/include/...base_sku=UPB10
http://www.amazon.com/APC-UPB10-Univ.../dp/B000GBN42E