My Z5‘s battery only can charge from 0% to 97% use the UCH20 （5v 1.5A）

I try another 5V 2A charger, the result was same.
It can get 100% but after 97% it take too long time to get another 1%(after 20 minutes, it haven't get 98%).
In HongKong the Z5 doesn't have a qucik charger.
Sorry for my poor English.