Apple developing solar-powered iPhones and iPods

The website, Patently Apple, which tracks Apple patent applications uncovered the Apple patents – called Power Management Circuitry and Cells – describing how handsets could be powered at least part of the time using solar cells.

'Some portable electronic devices (e.g., calculators) may use solar cells to power the device. Because of the small size of these portable electronic devices, however, the number of solar cells that can be placed on the device is limited. Consequently, while the voltage generated by the solar cells may be enough to power less energy demanding devices, the voltage may be insufficient for portable electronic devices that demand more power,' the patent filing notes.

Apple's patent addresses this by  covering most of the handset with a layer of transparent, or semi-transparent material to capture the solar energy, to maximise the amount of sunlight that can be harnessed.

Another feature of the patent, enables the solar power to variously charge the battery, supply power to the device or use extra battery power when there little solar power available, for example at night.