The 5 watt sunpower solar panel charges through a highly efficient power management consisting of two cells that together provide 6000mah storage volume a high quality converter uses the technology to provide 2 4 ampere output current on the usb a led status display shows when to recharge the batteries as a bonus there are two 1 watt lights at the back of the powertab that can be used for reading at night it takes less than 100 minutes in direct sunlight to charge your smartphone on the go