I have a Samsung Galaxy J3 (2016) I have recently lost my charger and I am using one that I had for one of my old phones it charges my phone only to 69% It shows it to still be charging but after an hour or so it's still on 69% why is that?
I suggest that you try using a different set of charger first. Also, try charging your phone while it's off. Let us know how it goes.