coconutBattery indicates iPhone 6 problem My iPhone 6 with ios 11.2.1 seems to lose charge too quickly. I connected my iPhone to my iMac and ran the app coconutBattery. the app reports the charge on my phone and the charge capacity. It also reports the design capacity. There is a bar graph which shows a red bar indicating charge current is at 42%. It seems even when my phone is completely charged, it reports full charge capacity is 819 mAh whereas design capacity is 1810 mAh or 42% as reported. This would explain why iPhone discharges so quickly. My question is, is there anything I can do to fix this?  I have included the coconutBattery window.
The issue here is that coconut battery shows that the design capacity is 45% and that app is probably correct.

This means that the battery is dying and needs to be replaced. 

This can be done by Apple or a third party. 

This question happened to be the first I read  on the way home after getting my battery replaced at an Apple Store. They need the phone for 2-3 hours. So book an appointment on line or as I did turn up and see if they have a spare slot, they will message you when they do (in my case after an hour). It cost £79.