Usb charging

Discussion in 'iPad 2 Forum' started by owenmorris, Mar 29, 2011.

  1. owenmorris
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    owenmorris iPF Novice

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    Hi guy's once again, the problem I have is that when I plug USB lead in my ipad2 says not charging. I always do a quick search before posting but found nothing.

    Owen
  2. Silent Assassin
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    Silent Assassin iPad Fan

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    It's charging, just VERY SLOWWWWLLLYYY... even though it's saying 'NOT CHARGING'..

    the iPad's charge block is rated 10W, and your USB port doesn't push enough power through it for it to trigger the charging icon... that is all..

    there is absolutely nothing wrong with your iPad..

    when charging on a laptop or desktop, be patient and enjoy... :D
  3. DontUnderstandMyIpad
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    DontUnderstandMyIpad iPad Guru

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    Have you connected the USB cable to a pc/laptop?

    The iPad draws a current of 10A and only the iPad wall charger supplies this current. A pc USB supplies a much lower current and will thus only trickle-charge the iPad.
  4. owenmorris
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    owenmorris iPF Novice

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    Tnx guy's for a real speedy response and answer appreciated.

    Owen (loving my iPad2)
  5. KJSmitty
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    KJSmitty iPad Fan

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    I hope it's not drawing 10A.... :). The battery would last only a few seconds if that.

    For the OP,

    USB only puts out around 5 watts and 1amp. That is why the iPad charges much slower connected to a PC/laptop vise the supplied 10 watt 2 amp power block.
  6. sjleworthy
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    sjleworthy Super Moderator Staff Member

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    Sorry guys, im missunderstanding something i think. So what's the normal optimal way to charge the ipad 2 then?
  7. majura
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    majura iPF Novice

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    @sjleworthy: Using and 'Made for iPad' certified 3rd party charger/USB adapter or the supplied power pack.

    Any other method such as connecting to a 'standard' USB port, other iPod/iPhone-only chargers will either (as mentioned) result in a extraordinarily slow charging time or only serve to reduce the battery loss of the iPad i.e. providing enough charge for the current battery level to remain the same or discharge the battery at a reduced rate than normal.

    Or if you have money to burn, a new SandyBridge generation MBP USB port will work just as well as the supplied power pack :)
    Last edited: Mar 29, 2011
  8. Silent Assassin
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    Silent Assassin iPad Fan

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    Optimal way is always with the supplied charger, but the USB port on your pc or laptop will do you just fine, so don't run out and buy anything..

    Have a little patience and just let it charge.. The battery on these things last 10 hours, they won't charge back up fully in 20 minutes, though we all wish they could... lol
  9. SweetPoison
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    SweetPoison iPad Legend

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    Plug it in the wall with the white cord it came with.
  10. SporkLover
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    SporkLover iPad Fan

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    What sweetp0ison said.

    I charge by USB once in a while, it's like a trickle charger.
  11. madhatter61
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    madhatter61 iPad Enthusiast

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    Double check your USB specs... it is my understanding USB 2.0 is limited to 500 milliamps (0.5 amps). USB 3.0 is 900 milliamps (0.9 amps).
  12. madhatter61
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    madhatter61 iPad Enthusiast

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    Double check your USB specs... it is my understanding USB 2.0 is limited to 500 milliamps (0.5 amps). USB 3.0 is 900 milliamps (0.9 amps).

    Actual current flow varies with the charge level required. If charge is really low, then the demand current wise is higher. As the charge reaches full, the current tapers off so as to not over charge. That is the regulators job. I know too much detail.
  13. KJSmitty
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    KJSmitty iPad Fan

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    No need to double check my specs. I already knew them as stated. Maybe you would have preferred "up to 1A".

    The only point worth taking away is something that has the capability to charge at 2A will charge the same battery faster than something capped at .5 or even 1A etc.

    Cheers
  14. Wolfpuppies3
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    Wolfpuppies3 iPad Junkie

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    Just use the 10 watt charger it came with

    You can buy another if you need it from guess where? your iPod or iPhone or USB port do not put out 10 watts, only the iPad charger does.
  15. madhatter61
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    madhatter61 iPad Enthusiast

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    If you read up on the specs of USB 2.0 you will find the max current is 500 milliamps ... that's 0.5 amps. USB 3.0 is expecting up to 900 milliamps.

    The Apple charger puts out 1 amp ... at 10 volts that would be 10 watts.
    Or if limited to 5 volts it would take 2 amps to equal 10 watts. Standard USB chargers won't charge your battery.
  16. KJSmitty
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    KJSmitty iPad Fan

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    Actually,,,,,,,

    1. Both USB and the iPad charger put out /charge at 5 "volts". (+ or - a small percentage)

    2. The iPad charger puts out/can charge at 2.0 "amps". (2.1 to be exact)

    3. Depending on the USB source, IE: your PC, car adapter, other plug-in style adapters etc, it can put out/charge "up to" typically 1.0 "amp" max.

    4. Thus, both charge at 5 volts yet the iPad charger can charge at 10 watts and the other between 2.5 and 5.0 watts. (volts x amps = watts)

    5. BOTH will charge the iPad.... Yet if only charging at 2.5 watts it will take significantly longer. Especially if the iPad is being used while charging. Basically the difference between a quick charge and a trickle charge. Never the less, both will charge unless the amps/watts provided during the charge are exceeded by the demand from the iPad battery etc.
    Last edited: Apr 1, 2011
  17. kaspia
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    kaspia iPF Noob

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    Energizer PowerPack PC007 iPad Adapter

    I am using the PC007 iPad Adapter by Energizer to charge my iPad when using a computer USB port.

    When possible, I always use the outlet adapter that came with the iPad. That adapter is just a neat accessory to have but not a necessity :D

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