"Not Charging" when connected via PC usb? LIES!

Discussion in 'iPad General Discussions' started by trale, Jan 14, 2011.

  1. trale

    trale
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    This must be a marketing trick from Apple to get people to buy more iPad-specific chargers. I left my iPad (80% battery) plugged into a PC laptop's regular USB port, and yes I get the "Not Charging" message. But when I came back an hour or so later - 100% battery!

    Anyone else notice this?
     
  2. Superbike81

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    It's not a trick.

    In order to get it to show that it's charging you have to have it connected to a higher power device. Most USB 2.0 ports do not have enough voltage for the iPad to recognize the charge. It is still charging, just much slower. Do a test for yourself, run your iPad down to 50% or so and connect it to your computer and then see how long it takes to charge to full. Then do the same test with the supplied iPad charger. It will be a big difference.
     
  3. peled

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  4. MachThree

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    A PC USB port will slowly charge an iPad if the iPad is off.

    If the iPad is on, then the amount of current put out by the USB port on most PC's is about the same as the iPad is probably consuming being turned on. The iPad's battery charge level might go up, might go down in this situation (i.e. if the iPad is on and doing nothing, it will probably slowly build a charge. If you're playing a 3D game, the charge might drop) But there's not enough current to guarantee its charging in any case so Apple elected to display "not charging" in this situation.

    On the other hand, if you plug the iPad into a wall charger, it will be charging fairly quickly no matter if its off or on or what its doing while on.
     
  5. SweetPoison

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  6. f4780y

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    My iPhone4 charger plugged into my iPad keyboard dock trickle charges my iPad nicely whilst at work...
     
  7. Seadog

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    Just like battery life is dependent on what you are doing, charging speed is the same. I will often plug into my laptop to charge, knowing it will take longer, but doing things with both at the same time. You should get 10-14 hours on a fully charged iPad, but running programs in the background will shorten that. OTOH, I have found that I can run music for 8-12 hours and hardly effect the battery charge.
     
  8. Ramesh

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    I have a iPad where the battery shows 2% or almost zero. I tried charging with original Adopter but it fails to charge. I switched off iPad and to my surprise it charged unto 40% within 10 hours but while keeping on it again failed to charge further. On connecting with my Pc it fails to be detected. I wonder what could have gone wrong as I have used another Adopter from apple and situation remains same. This is almost have happened in three ipads in my group. Any body facing this issue who would have found the solution
     
  9. Tinman

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    Not true in my tests. I have set my ipad to never sleep and it still tops off.

    It's pretty simple. There is from 1 amp to 2 amps charging it @ 5v so 5-10 watts. Obviously it will take twice as long at 1 amp than 2.

    The iPad has a 3.75V, 24.8 watt-hour battery. For arguments sake if we assume the extra voltage from USB is lost as heat then we can assume it would take about 2.5 hours to fully charge at 2 amps versus 5 hours at 1 amp. (In practice it is not likely charging at full amperage for the duration of charging: the last 5 or 10 percent it likely steps down a bit.)

    Most usage patterns yield more battery life than 5 hours.

    Ergo in theory you should still get a net positive charge even from a 1 amp USB port, even with iPad on. In practice this is the case for me.




    Michael
     

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