How fast does it charge while in use? Mine doesn’t really gain or lose charge if I’m using it and charging it at the same time.
It’s like that with standard charger or cable because most current is going to power device not battery but you can make a big difference with a quickcharge type:
ORICO QTW-1U 1 Port Travel Wall Charger With Qualcomm Quick Charge 3.0 with 1m Free Micro USB Cable
http://s.aliexpress.com/qQFvUriY
(from AliExpress Android)
With this one it can charge powered on.