Charging an iPhone, difference between USB port and power outlet The power outlet has more power obviously, but maybe the computer USB is suffice to charge it at maximum speed.

Is there a difference between charging an iPhone using the computer USB port and using the power outlet?
Here is a page where you have the result of the comparison of charging an iPhone4 from USB or power outlet.
Here is their conclusion:


  Stating the obvious, the iPhone 4 takes longer to get a full charge on USB than an outlet. What you may not have realized is how big the difference was, an extra 30 minutes! That’s 23% longer to get a full charge on the USB.