Charge And Monitor The Battery
iPad has an internal, lithium-ion rechargeable battery. For more information about the battery- including tips for maximizing battery life-see www.apple.com/batteries.
Charge the battery. The best way to charge the iPad battery is to connect iPad to a power outlet using the included cable and USB power adapter.
iPad may also charge slowly when you connect it to a USB 2.0 port on your computer. If your Mac or PC doesn't provide enough power to charge iPad, a "Not Charging" message appears in the status bar.
The battery icon in the upper-right corner of the status bar shows the battery level or charging status.
Display the percentage of battery charge. Go to Settings > General > Usage and turn on Battery Percentage.
Rechargeable batteries have a limited number of charge cycles and may eventually need to be replaced. The iPad battery isn't user replaceable; it can be replaced only by an authorized service provider. See www.apple.com/batteries/replacements.html.