Original post by: Chris Tee ,
I have had a similar problem with my iPhone 6. What worked for me was re-calibrating the battery. Now this may not work for you as there can of course be multiple problems, but is worth a shot. # Firstly charge up your phone fully, and once at 100% leave charging for an hour or so more. # Now unplug and use your phone like normal. # Take it all the way down to 0% and allow it to die. # Ideally you want to leave it overnight or for 4+ hours with the battery dead. If you cannot do this allow it to be dead for as long as you can. # Now recharge the phone fully and it should have recalibrate the phones battery. I hope that this helps.