Welcome to iMore. I was advised by an iMore member to let my battery die all the way (approx 2%) on my 5s until the iPhone turns itself off, then let it charge to 100% without touching it.....IT WORKED, my battery lasts a whole lot longer on the average. I started doing this once a month and now continue to do this with my iPhone 6Plus. Not sure how/why it works but it did.....Enjoy iMore.