Originally Posted by Hadron
Charge when shut down, fine. But why run it flat? That's not good for battery longevity.
The theory behind this process is that by running it flat and recharging until full (while off) it forces to sync the battery level values and it's battery cycle values when the phone powers on and detects the full charged state.
Yes your right about running the phone flat, but this is one way of making sure that the phone detects a full charge cycle has been completed IMO, but if you don't feel comfortable allow it to run under 10% and then turn off and charge until full, that should result I'm a full cycle as well.