This is what I don't like about the manufactures, the USB charging doesn't function properly when plugged into a laptop, and if it does you can't use the tablet and it's incredibly slow.
When I travel (which I do frequently) I don't want to stand by a charging station, I want to sit in a chair and charge the tablet through my laptop as needed. Right now I have a 2014 Note 10.1 and plugged in using the proper connections it takes 8 hours to charge from 0 - 100% and 4 hours from 75% - 100% through my outlet. Whereas my iPad Mini and iPad 4 take 3 hours from 0-100% using an outlet or my laptop while still using the tablets. Gah, failure on android manufacturers part.