Originally Posted By: jimbrewer
Who needs fast? If I can put it on it's cradle for an hour here and there where it would not be charged by conventional means and then overnight, I'm good. What do I care if the phone doesn't fully charge until 200 am instead of midnight?
You're actually extending your lithium ion battery's longevity that way.
Charging to 100% and discharging all the way drastically reduces the number of charge cycles the battery can go through before it's capacity drops significantly. Fast charging also generates more heat which is a further problem.
If the lifecycle of the phone is a year or two, then it's not a problem because the user has gotten maximum performance out of the battery for the time they've owned the phone. But if you want to keep the phone longer and not change the battery, and you don't need a full charge every day, then you'll want to charge it more like an electric car is charged (max charge of 80% of original capacity and range is "empty" at 30% of original capacity). On those occasions when you need the full capacity of the battery, then leaving the phone charging for a little longer and discharging the battery more is going to reduce the life of the battery but you're not doing it every day when you don't need to.
I now charge my phone to 70% max which is enough most of the time. My goal is to not discharge below 20%. I have a charger in the car which helps keep me in this range and I have an app that buzzes me when I reach 70%. It is also possible to switch off charging at a preset % (requires root).