The iPad actually will charge from a normal USB port, but not while the screen is on. If you hit the sleep button it will start charging, you just can’t tell because the screen is off. As soon as you turn the screen back on, it says ‘not charging’ next to the battery. Brings to mind the classic refrigerator light dilemma.

That’s the good news. The bad news is that it charges slooooowly. I tested this out last night. Over the course of 8 hours it charged from 10% up to 60%. So while you can charge your iPad over USB, it’s hardly practical. I’ve read that the high power USB ports on certain Macs work a bit faster, but the wall outlet is still by far the fastest way to charge.

The next test: Does the iPad lose battery power if you are using it while hooked up to a normal USB port? Or does it use the USB power to operate while leaving the battery untouched