I thought the USB (Synching) doesn't charge the iPad?

[bembol]

It even says, "Not Charging" but I woke up just now to find my (64GB/3G) iPad fully charged.

Did Apple made changes to 4.3.1?

 

[Intell]

Even when the iPad says "Not Charging" it charges, but at a very, very slow rate.

 

[darngooddesign]

I'm not sure why yours doesn't say that its charging because it does.

 

[sandman42]

It depends on the computer. Some (generally newer) USB ports can provide enough power to support the current draw the iPad needs to charge, but older ones have a lower current rating that doesn't necessarily support the iPad. It looks like the iPad will say "not charging" if connected to a USB port that doesn't have the specs to support, even if the iPad is actually charging, though at a slower rate.

It's similar to the "bricks" Apple provides for charging. The smaller iPhone "cube" is rated at 5W (as I recall), and the larger one supplied with the iPad is 10W. I plug my iPad into the iPhone charger fairly often and it does charge, but I think it's slower than the 10W iPad charger.

See this article on Apple's support site.