Long Charging Time with Sys Activity App

[mlstne]

My Ipad4 is three months old. I have used SysActivity App to recharge from less than 10% five times, the first four took roughly 6 hours each, the last one over 16 hours and the battery was very warm. The next time it dropped to 10% SysActivity projected 16 hours to charge. I did not activate the app, used the OEM charger and the battery was charged in +/_ six hours. Is the long charging time normal for this app or do I have an app or battery problem? Thanks for your help.