The manual for the Thunderbolt display says the USB ports can be used to charge iphone / iPad. The new iPads (4th gen) come with a 12w charger.
What is the power rating on the Thunderbolt Display's USB ports? Is it at least 12w?
The Thunderbolt Display's USB ports are 5 Volts and have a maximum current available of 500 mA (which equals 2.5 Watts maximum). This does not mean you cannot charge your iPad from the USB, it will just be much slower and require you to limit use on the iPad while charging.
Much slower indeed. What is the source of your answer?
USB is nominally 5 Volts. The maximum available current I looked up in system information (/Applications/Utilities/System Information.app) for my Thunderbolt Display which is given as 500mA. Power equals voltage multiplied by current which results in 2.5W.
Yes, I understand P = IE, but didn't know I could find the available current data in the Sys Info.
At only 2.5w, a full charge of the 42w/hr battery via the Mac or Thunderbolt monitor would probably take 18-24hs given the non-linear charge curve. An overnight charge might put back half the capacity.
Since the included iPad 4 charger puts out 12w, it is clearly the charger of choice!
Thanks!
I was looking for more detailed information on these ports and came across this incorrect information (and since it shows in google, yes I'm replying to an old thread). The display can certainly provide 1A to Apple peripherals.
After plugging my iPhone into my thunderbolt display I opened system information and it has this (Extra operating current is what is important here):
iPhone:
Product ID: 0x12a8
Vendor ID: 0x05ac (Apple Inc.)
Version: 8.02
Serial Number: xxxxxxxxxxxxxxxxx
Speed: Up to 480 Mb/sec
Manufacturer: Apple Inc.
Location ID: 0xa0110000 / 8
Current Available (mA): 500
Current Required (mA): 500
Extra Operating Current (mA): 500
Power output from USB ports
