Zte Telstra Qwerty-Touch User Manual page 13

 Normal charge time is 3-4 hours. Do not leave on charge for
more than 24hrs.
 After 2-3 charge / discharge cycles the battery life will
improve. From then on use top up charging to recharge
frequently and always charge promptly when flat.
 When not using the phone for long periods charge to approx
40% and remove the battery.
 With poor network conditions (less than 2 bars) battery life is
reduced.
 Turn off Bluetooth when not in use to extend battery life.