Today I decided to see exactly how long my iPhone battery would last with moderate use. Once I enabled Low Power Mode (https://goo.gl/8BUk5l), did this at about 70% left, my phone lasted about 14 hours. I think that if I enabled it as soon as I take it off the charger, I could possible get 18, maybe 20 hours out of it…..Guess that’ll be the next test