My iPhone 6 has a problem charging My iPhone 6 has a problem charging it will charge then not charge then it will repeat it. When it gets to 100% and it get taken off the charger then a few minutes it will die. 

What do I need to do to fix it?
If you can connect your battery to a Mac, get the app CoconutBattery and run it with your iphone connected to the Mac. It will tell you if iPhone battery is charging properly. I used it with my iPhone 6 and it correctly identified that battery was faulty and not charging properly. I took my phone in for a new battery.