iPad doesn't charge via USB --> Computer?

[Prof.]

Is this becuz the iPad battery is too big to be charged by a computer? I don't mind plugging it into an outlet, but it is a bit inconvenient.

 

[Intell]

Its because the iPad wants 10 watts of power. But the computer cannot provide that much energy because it is outside the range of normal USB ports. Some computers can charge the iPad, but at a slower charging rate.

 

[Tomple]

What computer do you have
some don't have the power to charge via usb

 

[Prof.]

Oooooooooh that makes sense!

I have a MacBook LOL!

 

[mpsruo]

That's correct, it cannot be charged by USB. It also CANNOT be charged even by a powered USB hub. It can, however, MAINTAIN (somewhat) of its battery level by being plugged into your macbook's USB port

 

[Prof.]

Thanks for the replies!

Side note: This is day two of continued use and my iPad has just hit 60% battery life. This thing is AMAZING!

 

[Don Kosak]

My 2007 iMac charges the iPad (through the back USB ports, but not through the keyboard ports.) It charges it a bit slower than the wall charger.

My black MacBook says, "Not Charging".

Some computers have "high power USB 2.0" sockets on them. Some computers have only 1 high power socket, which might not be market any differently. The iPad will only charge when plugged into one of these high power sockets.

All of the new iMacs and MacBook Pro's have high power USB. I'm not sure about other makes or models.

 

[miklovo]

My MacBook pro charges my iPad but slowly. I'll leave it plugged in overnight and it's charged in the AM, as opposed to just couple of hours plugged into the wall.

 

[KevinC867]

My MacBook pro charges my iPad but slowly. I'll leave it plugged in overnight and it's charged in the AM, as opposed to just couple of hours plugged into the wall.

+1

My iPad says "Not Charging" when plugged into my MacBook Pro, but it does charge slowly.

 

[Tom G.]

My iMac will charge my iPad but at a slower rate.

I use my iPad as an alarm clock at night so therefore plug it into a wall socket so it charges instead of discharging. This also means it is fully charged each morning.

 

[rgarjr]

Its because the iPad wants 10 watts of power. But the computer cannot provide that much energy because it is outside the range of normal USB ports. Some computers can charge the iPad, but at a slower charging rate.

Yeah the computers USB port is rated at 500 milliamps, (P=VI) 5volts X .5amps is 2.5W. Computers USB port can only supply 2.5 watts.

 

[Don Kosak]

The official write-up on iPad USB charging is at:
http://support.apple.com/kb/HT4060

Old style USB ports do 500ma. They will not charge iPad.

A lot of newer USB ports, comply with the high-power or battery-charge standard that increases the current to 1100ma or greater. When in charging mode, some USB ports can not do high speed transfers - it depends on the chipset.

You can read more about Apple's USB ports in this second document that discusses the differences between high power and standard USB:
http://support.apple.com/kb/HT4049

 

[madmole]

Easy to fix

Go to http://event.asus.com/mb/2010/ai_charger/

Download the driver and there is a good chance your USB will now output enough to charge the iPad