The battery icon in the upper-right corner shows the battery level or charging status. You can also display the percentage of the battery charge (iPhone 3GS only).
Connect iPhone to a power outlet using the included Dock Connector to USB Cable and USB power adapter.

Connect iPhone to your computer using the included Dock Connector to USB Cable. Or connect iPhone to your computer using the included cable and the Dock, available separately.
Unless your keyboard has a high-powered USB 2.0 port, you must connect iPhone to a USB 2.0 port on your computer.

IMPORTANT: The iPhone battery may drain instead of charge if iPhone is connected to a computer that’s turned off or is in sleep or standby mode.
If you charge the battery while syncing or using iPhone, it may take longer to charge.
IMPORTANT: If iPhone is very low on power, it may display one of the following images, indicating that iPhone needs to charge for up to ten minutes before you can use it. If iPhone is extremely low on power, the display may be blank for up to two minutes before one of the low-battery images appears.
