Currently Being ModeratedNov 30, 2012 2:17 PM (in response to dabigmac)
Your PC's USB port appears not to be putting out sufficient current to charge the iPad, or charges it so slowly that it's difficult to notice. This is not uncommon, particularly with laptops but also with some desktop USB cards. You could try a powered USB hub, but you'll want to confirm that the hub also puts out sufficient current.
Or just use the AC adapter.
Currently Being ModeratedNov 30, 2012 6:50 PM (in response to dabigmac)
The quickest way (and really the only way) to charge your iPad is with the included 10W or 12W 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
How to Save and Prolong the battery life of your new ipad
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.
Currently Being ModeratedDec 1, 2012 6:44 PM (in response to Texas Mac Man)
Texas Mac Man, has got it right.
I had problems with slow charge (10 hours) time for the new ipad 4 retina display.
What I did not realise was that even though the iPhone 5 and the iPad chargers look the same the former is 5W and the latter 12W. Stupid me hadn't even bothered to take the iPad charger out of the box.
Finally I checked it out and now get a zero to full charge in 4 hours.
Hopefully this will help anyone who is making the same mistake.
Lucky that I didn't take the iPad back to the store as I would have looked like a total idiot.