We've just written a new article about this topic. It focuses a lot on charging Apple's devices like iPads and iPhones but has general info relevant to all devices. Take a look and let us know what questions you have: plugable.com/charging. If the link to the article gets removed from this post, you can find it on Plugable's website as "Charging Your iPad or iPhone with a USB Hub" in the Posts section of the website. Let us know what questions you have after reading it.