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When I plug my iPad into my computer's USB ports, the iPad battery area displays "Not Charging".

I understand the iPad requires more wattage to charge compared to an iPhone or iPod, as evidenced by the iPad's larger power adapter (10W) vs the iPhone's (5W).

Is there anything I can do to enable iPad charging from my computer's USB ports? The computer in question is a desktop PC, and it has a 950W power supply. I presume the motherboard's own USB ports are the issue, as opposed to overall power available :-)

So I'd like to know:

  • Are there external USB hubs that can supply enough power to charge the iPad?

  • Is there any other solution to enable a computer's USB ports to charge an iPad?
    e.g. doubling up a USB port, as I've seen done with some external hard drive enclosures?

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6 Answers

up vote 21 down vote accepted

From the article, The iPad's USB charging caveat:

[Originally posted on Neowin.net by giga on 04 April 2010 12:26]

The iPad specifications page clearly state the ability to charge with USB (with no mention of OS requirements) but Apple have additionally provided a support document disclosing that "some USB 2.0 ports and accessories do not provide enough power to charge iPad."

Providing some further clarification to Macworld, Apple asserts that USB charging is supported but that it varies according to the state of the iPad and the power output of the USB hub:

  • For the fastest charging, use the iPad’s included 10-Watt USB power adapter. This will fully charge the iPad in a few hours, even if you’re using the iPad at the same time.
  • When connected to a high-power USB port—such as the ones on recent Macs and the iPhone Power Adapter—the iPad will charge, even during use, but more slowly. (We haven’t yet determined how much more slowly.) Some third-party powered USB hubs provide higher-power USB ports, but many don’t; similarly, the USB ports on most Windows PCs don’t provide this additional power.
  • When connected to lower-power USB ports—those on older Macs, most Windows PCs, and most USB hubs (powered or unpowered)—the iPad’s battery is not charged while the iPad is awake, but is charged (again, slowly) when the iPad is asleep. What’s confusing here is that the message "Not charging" appears in the menu bar when the iPad is awake, which might lead you to assume that the offending USB port can never charge your iPad. But rest assured, Apple says: once you put the iPad to sleep, the battery will indeed charge. (If you could see the screen while the iPad was asleep, it might even display the charging icon. It’s the modern-day “Does the refrigerator light stay on when I close the door?” mystery.)

Further analysis from Apple's statements indicate that the iPad can only be charged off of USB connections that provide near 1 amp of current. The majority of USB ports on most older Macs and PCs only provide 500 mA and thus can't be used to charge the device.

The USB 2.0 specification provides 500 mA of current to high-powered buses and 100 mA for low-powered buses. But in April 2009, the specification gained a new "Battery Charging Specification" which provided additional current to high power devices and it seems that Apple has started to incorporate it in their newer Macs.

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+1 - my experience too. I've yet to find a USB hub (or a port on any of my Macs and Dell PCs) that will noticeably charge my iPad. –  robsoft Aug 19 '10 at 12:17
    
+1. Especially the point the iPad's battery [...] is charged (again, slowly) when the iPad is asleep. I confirmed this; took my 50% charged iPad to 91% after a few hours, even on a USB port that had it displaying "Not Charging" when the screen was active. Thanks! –  Chris W. Rea Aug 23 '10 at 21:14
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Thanks for the clarification. I wonder if my MacBookPro2,2 manages to charge it off either ports, system info says it both requires and uses 500 mA. And I don't have a charger either, could my iPad have toasted the old iPhone charger (not the slim type, same shape as iPad charger...) –  HiQ CJ Jan 10 '11 at 12:44
    
What I need is simply a bulk 220V->USB transformer, there simply are too many devices which require it now. Because Apple devices are not doing any particular tricks, are they? They should be able to use any charger providing sufficient amperage? We've had some challenges in the car... –  HiQ CJ Jan 10 '11 at 12:45
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Interestingly, my cheap-o powered USB hub does not seem sufficient, and even though they are identical in dimensions, the old iPhone and new iPad charger are not the same, the latter is 2.1 A (50W) and the old one is a seemingly insufficient 1 A. –  HiQ CJ Jan 10 '11 at 19:35
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As Am1rr3zA mentioned above, the specs for USB 2.0 provides for 500 mA of power. Apple is the sole manufacturer that I know of that utilizes higher-than-spec powered USB ports, and I think, even then that's only on their later model (within the last couple years) Macs.

"Not charging" is a bit of a misnomer, because in fact, the iPad is charging, but it's also draining power. It says "Not charging" when it's draining power quicker than it's charging, which is the case when plugged into 500 mA USB ports. There's nothing you can really do about this, unfortunately.

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The same thing happened to me "Not Charging" but when I inserted my motherboard support cd i saw a software called "ASUS Ai Charger" then i installed it and restarted. Then when i plugged in my iPad mini it charged

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Check if there is an update for your motherboard, many manufacturer has release update to enable USB port to deliver enough watt to charge an iPad.

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This is one of many cases in which a device that says it's not charging is actually... charging... very... slowly.

This is the case with the ipad here, ipods and iphones that are put into older docks, blackberries that are connected to older macbooks, etc.

You'll likely be just fine if you charge it overnight, but if you're waiting for it, it's pretty darn slow.

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USB 3.0 is specified for up to 900 mA. Give such a hub a try.

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I think USB3.0 is actually 2A? Thus Apple are not "the only ones" supplying 2A USB ports. –  user12798 Oct 26 '11 at 8:22
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