You have to notice that the improper connection of battery on battery connector causes that most of the issues,
That the following reason might be check it step by step.
Charging port might be dirty.
battery connector loose connect.
The BSI point of battery connector and near parts broke down ,open or remove unknowingly while falldown or battery replace.
The must know about the Bsi point and it`s [http://www.thegsmsolution.com/2017/12/iphone-5s-battery-percentage-1-only.html|function check this] the process.