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TC81
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Posts: 10
Registered: ‎05-18-2014
Location: Australia
Views: 1,607
Message 1 of 5

W540 - USB Charging iPad Issue

I have recently purchased a W540 and a Thinkpad Ultra Dock 135W. Is there a reason why none of the USB ports on either the laptop or dock can charge an iPad 2? I have tried them all and only get the message "Not Charging" on the iPad. I believe it is a power output issue but have no idea why and would have expected at least one USB port to be able to charge? I have the dock connected to permanent 240V power as well?? Help!!!
lead_org Microsoft MVP Contributor
Microsoft MVP Contributor
Posts: 21,009
Registered: ‎12-19-2008
Location: Australia, Melbourne
Views: 1,566
Message 2 of 5

Re: W540 - USB Charging iPad Issue

The iPad needs 10 Watts USB to charge it. The laptop can't provide that much power through its USB. However even though it says it is not charging when connected to the laptop, it is actually charging it at a slower rate, called trickle charging. Leave it overnight and the battery meter will change.
Regards,

Jin Li

May this year, be the year of 'DO'!

I am a volunteer, and not a paid staff of Lenovo or Microsoft
TC81
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Posts: 10
Registered: ‎05-18-2014
Location: Australia
Views: 1,555
Message 3 of 5

Re: W540 - USB Charging iPad Issue

Hi Jin,

 

I thought that was the case but curious as to why my MBP and my work HP laptop can do it without issue?  I was hoping as i bought a top end workstation it would have the capacity?

 

Even the dock connected to power can't supply enough?

Guru
Posts: 9,598
Registered: ‎12-26-2009
Location: CA
Views: 1,542
Message 4 of 5

Re: W540 - USB Charging iPad Issue

The USB standard only allows a certain amount of power. Some manufacturers choose to ignore this upper limit and allow higher currents.

There is however a workaround to it with an unofficial tool from Gigabyte:
http://www.gigabyte.com/support-downloads/Utility.aspx?cg=2

This was reported to work a while back, but I've never tried it myself. It may or may not still work on Haswell machines.

W520: 2960XM, Q2000M @ 1091/1380, 32GB RAM, 500GB&750GB HDD & 500GB SSD, FHD&MB168B+
X61T: L7500, 4GB RAM, 500GB HDD, XGA screen, Ultrabase
W550s: 5600U, K620M at 1164/1281, 16GB RAM, 512GB SSD, 3K touchscreen
X200s: SL9400, 6GB RAM, 64GB SD card, WXGA+ screen
TPT1: 1839-23U
lead_org Microsoft MVP Contributor
Microsoft MVP Contributor
Posts: 21,009
Registered: ‎12-19-2008
Location: Australia, Melbourne
Views: 1,531
Message 5 of 5

Re: W540 - USB Charging iPad Issue

As the Colonel said, many manufacturer choose to follow the USB standard and restrict the maximum power available to the USB port. While other companies like Apple, whom produces iPad have USB port that can provide the full 10 W power to their USB.
Regards,

Jin Li

May this year, be the year of 'DO'!

I am a volunteer, and not a paid staff of Lenovo or Microsoft

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