I seem to be able to charge my iPhone 5 on a variety of USB chargers (car ones included). My iPad retina (iPad 4) seems to be very fussy about which chargers it will actually charge up on. (The charging icon will come on, but the charge won't increase even after two hours).

My question is, what causes this? Does the iPad draw more current when charging?


The recommended power for an iPad charger is 12W. The power of the iPhone charger is 5W.

So you should get the iPad charger to charge your iPad.


The iPad, having a bigger battery, is designed to pull up to 2.1 Amps at 5V. Most chargers are designed to be 5V at a max of 500mA. That 500mA is divided into both charging the iPad and running it at the same time. If you have the iPad on and doing stuff, most of the power being supplied is going to running, which will make charging take forever. When you can, plug it in, then turn it off.



See https://android.stackexchange.com/questions/78285/are-apple-android-specific-usb-charging-ports-really-different.

The standard USB (1.0 and 2.0, anyway) spec only allows for 500mA. There are multiple incompatible protocols for drawing more. Apple's work differently than others.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .