This info from the Users Guide may help:
The color of the status indicator tells the battery status of your mobile phone.
2.2.4 Important Information About the Battery
If the battery has not been used for a long period of time, you may not be able to power on your mobile phone immediately after you begin charging the battery. Allow the battery to charge for a few minutes with the phone powered off before attempting to power on the phone.
The battery will not hold a charge for the way it did when it was new. When the battery life becomes noticeably shorter than usual after being charged properly, replace the battery with a new one of the same type.
Using data services increases demand on the battery and will reduce the length of time it can hold a charge.
The time required to charge the battery depends on the ambient temperature and the age of the battery.
Status indicatorGreen: Fully charged (when connected to charger).Orange: Charging in progress (when connected to charger).Red: Battery low.
When the battery is low on power, the phone plays an alert and displays a prompt. When battery power is almost exhausted, your phone will power off automatically.
2.2.5 Battery Saving Tips
The longevity of battery power depends on the network that you connect to, and how you use your
Try the following to conserve battery power:
When your mobile phone is not in use, switch off the screen.
Reset the time it takes for your screen light to switch off when you leave your phone idle.
Lower the screen brightness.
Use the AC adapter to plug your phone into an external power source whenever possible.
Turn Bluetooth off when you are not using it. Only make your phone visible to other Bluetooth devices when you need to establish a Bluetooth connection.
Switch off Wi-Fi when you are not using it.
Turn off your phone connection to GPS satellites when you are not using it.
Lower the volume.
Close power-draining programs, when you do not need them.
Turn off the data service.
Lithium batteries should not be allowed to go completely flat!
If you allow this to happen - DON'T POWER ON THE PHONE WHEN YOU FIRST START CHARGING!
- wait until the battery has been on charge at least a half hour. Cheers Neil.