If you have a new phone you have to know that:

1. If your phone battery is Nickel based then you have to charge it for 12 hours, 3 times.
2. If your phone battery is Lithium based then it's enough just one charge of 12 hours.
3. To extend your battery life (works for Nickel and Lithium) it is recommended to fully discharge your phone before you start the charging process.