So charging between say 20%-80% is the ideal range to get the longest overall battery life? It's early for me right now, my brain is still waking up
Yes, the expected lifespan of a battery under typical usage/charging patterns (when it will no longer hold a charge that's at least 80% of rated capacity), is 500 complete charge/discharge cycles, where a complete cycle is the charging and discharging of 100% of the battery's capacity. So if you charge to 100%, use to 50%, charge to 100% and use to 50%, you have completed 1 (not 2), complete 100% charge/discharge cycle.
So for the typical user, that battery should last about 1.5 to 2 years before it will only hold about 80% of its rated capacity. If you charge as you indicated, staying between 20% and 80%, you could extend that to 2,500 cycles! Now there are other limits - namely the "shelf-life" of the batteries, which is between 3 and 4 years typically, so even if you charged and discharged in that 60% range, you may never actually get 2,500 cycles since time continues ticking away no matter what your charging and discharging practices are.
Then there's the "effective" lifespan - where the battery has served its intended purpose and the PHONE is no longer a viable device when compared to newer devices of that time. What does this mean? It means you probably will replace the phone LONG before the battery reaches the 80% capacity limit if charging in the 60% range. Truth is, you may even replace the phone before 1.5 years, so the expected lifespan of 500 cycles works relatively well for most people.
What it will do for you though, is provide longer run-times during that 1.5 years or so, but it also means you'll be plugging into the wall more often. For me, that's not a problem since I have a car Navigation Dock and a Desktop Dock, so when I'm not carrying the phone, it sits in one or the other, giving it frequent "boost" charges. This is the preferred method of charging for this battery's chemistry, and will result in the longest lasting battery.
