Originally Posted by
klam28 Since I've gotten my iPhone 6, I've been hesitant to leave it charging overnight. Recently, I've been using BatteryLife to monitor my battery's health and it reported that my battery currently holds 86% of it's original capacity. This leads me to believe that the my charging habits haven't exactly improved my battery's lifespan, if after a little over a year it's health has dropped 14%. For the record, it has gone through approximately 350 charge cycles to this point. I now use a battery case and it is one of the best decisions I have made.
I use BatteryLife when I'm jailbroken as well. What I did with my iPhone 6 was I did a full-charge cycle (from 0–100 and leave it plugged in for an extra hour passed 100% to fully calibrate) once every 2-3 months, otherwise I'd plug it in as soon as it drops to 20% and unplug when it reaches the mid-80s. This is so as to reduce the number of charge/power-cycles. Basically, if your phone drops below 21% and you plug it till 100% it'll count as a full charge/power-cycle and its best to keep this as low a number as possible. According to Apple, at 500 charge/power-cycles your iPhone will retain equal to or less than 80% of its battery capacity, at which point the battery is no good and will discharge much faster than originally.