Currently Being ModeratedOct 18, 2012 7:01 AM (in response to SOCSTAR1)
The iPad requires more power than the iPhone to charge it (its wall charger is 10W as opposed to the iPhone's 5W), and a lot of computers don't provide enough power to their USB ports to charge the iPad at a sufficient rate - it may still be charging slowly, and should be a bit quicker if the iPad's screen is off (if you leave it for a while and then disconnect it from your computer you may find that it's battery percentage has gone up). The wall charger is usually the most efficient way to charge the iPad.
Charging the iPad : http://support.apple.com/kb/HT4060
Currently Being ModeratedOct 18, 2012 7:03 AM (in response to SOCSTAR1)
The USB port probably doesn't have enough power for the iPad (requires more than the iPhone). Its possible it will actually charge if left plugged in long enough, but will take a very long time and may not give you a complete charge. Your best bet it to use a wall outlet.
Currently Being ModeratedOct 18, 2012 8:10 AM (in response to SOCSTAR1)
The quickest way (and really the only way) to charge your iPad is with the included 10W USB Power Adapter. iPad will also charge, although more slowly, when attached to a computer with a high-power USB port (many recent Mac computers) or with an iPhone Power Adapter (5W). When attached to a computer via a standard USB port (most PCs or older Mac computers) iPad will charge very slowly (but iPad indicates not charging). Make sure your computer is on while charging iPad via USB. If iPad is connected to a computer that’s turned off or is in sleep or standby mode, the iPad battery will continue to drain.
Apple recommends that once a month you let the iPad fully discharge & then recharge to 100%.
How to Calibrate Your Mac, iPhone, or iPad Battery
At this link http://www.tomshardware.com/reviews/galaxy-tab-android-tablet,3014-11.html , tests show that the iPad 2 battery (25 watt-hours) will charge to 90% in 3 hours 1 minute. It will charge to 100% in 4 hours 2 minutes. The new iPad has a larger capacity battery (42 watt-hours), so using the 10W charger will obviously take longer. If you are using your iPad while charging, it will take even longer. It's best to turn your new iPad OFF and charge over night. Also look at The iPad's charging challenge explained http://www.macworld.com/article/1150356/ipadcharging.html
Also, if you have a 3rd generation iPad, look at
Apple: iPad Battery Nothing to Get Charged Up About
Apple Explains New iPad's Continued Charging Beyond 100% Battery Level
New iPad Takes Much Longer to Charge Than iPad 2
Apple Batteries - iPad http://www.apple.com/batteries/ipad.html
Extend iPad Battery Life (Look at pjl123 comment)
New iPad Slow to Recharge, Barely Charges During Use
Tips About Charging for New iPad 3
Prolong battery lifespan for iPad / iPad 2 / iPad 3: charging tips
iPhone, iPod, Using the iPad Charger
Install and use Battery Doctor HD
In rare instances when using the Camera Connection Kit, you may notice that iPad does not charge after using the Camera Connection Kit. Disconnecting and reconnecting the iPad from the charger will resolve this issue.