Why does my device go to sleep?

"Power-Saving mode" will cause your device to go to sleep when using solar power.

Devices that use solar power will need to go to sleep to conserve power. This ensures that your device has enough power to operate at peak times when sunlight may not be available. 

When the device is in power-saving mode, you can wake it up by pressing any key on the keypad. It will take about 2 minutes to wake up, and stay awake for 5 minutes from the last activity on the device.