Micro USB port and external hard disks

Discussion in 'hardware' started by aigle, Aug 8, 2015.

  1. aigle

    aigle Registered Member

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    What is the experience of you guys? Do micro USB ports provide enough power to connect and use an external hard disk?

    I have a Windows tablet with a micro USB port and if I connect an external hard drive via an OTG cable it does not work unless I provide more power to the external via an additional USB cable.

    I checked on net and the US conflicting evidence. Some people are claiming that their external hard disk with via ordinary OTG cable and don, t need extra power. They claim that if OTG cable fails, it is only because the cable is not a true OTG cable.

    Others claim that OTG can't provide enough power for external hard disks and they use a special OTG cable with an extra USB cable for power or they use a powered USB hub.

    What is your experience?

    Thanks
     
  2. aigle

    aigle Registered Member

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    Can some mod change the title to

    Mocro USB port and external hard disks

    Thanks. It was auto correct from swipe and I am not finding option to edit title on mobile.

    :)
     
  3. J_L

    J_L Registered Member

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    Your external hard drive has 2 USB ports? What size is it?

    Well I just tried a WD My Passport Ultra on my Nexus 5, and unsurprisingly it doesn't work. Flash drives are no problems though.
     
  4. stapp

    stapp Global Moderator

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    Done, although I put Micro instead of Mocro as I'm sure thats what you meant :)
     
  5. aigle

    aigle Registered Member

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    Oh yes please. Thanks a lot.:)
     
  6. aigle

    aigle Registered Member

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    only one port. When I say extra USB cable for power, I mean the cable that has two wires attached to a single port.
     
  7. aigle

    aigle Registered Member

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  8. Snoop3

    Snoop3 Registered Member

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  9. Raza0007

    Raza0007 Registered Member

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    aigle,

    Typically micro usb ports have to follow the power specification of the respective standard usb port. Which type of micro usb port is it 2.0, 3.0 or 3.1?

    Usb 2.0 can provide max 0.5 Amps, while 3 and 3.1 can provide 0.9 Amps.

    Maybe the device limits the output power of the micro usb port to conserve battery. Which tablet is it? Have you checked the tablet's manual?

    Try connecting your external HDD while the tablet is connected to its charger and see if then it will provide full power to your external HDD.
     
    Last edited: Aug 8, 2015
  10. Snoop3

    Snoop3 Registered Member

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    will be nice when USB C gets here
     
  11. Raza0007

    Raza0007 Registered Member

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    Its already here, it is now up to the manufacturers to implement it in their products.
     
    Last edited: Aug 8, 2015
  12. aigle

    aigle Registered Member

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    It is Lenovo miix 2 8 with micro USB 2 port( only one port that is also the charging port fortunately/unfortunately).
     
  13. Raza0007

    Raza0007 Registered Member

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    OK. So now I understand what you are asking.

    You are using the tablet's micro usb charging port to function as a regular usb port. The problem with this is that this particular micro usb port is not designed to communicate with external devices or to supply power to external devices. The stop gap measure is using a usb OTG cable, to turn your tablet into a host, which is what you are doing.

    Even though this port is cable of receiving 2 Amps of current and 10 W of power from the charger, it is probably not configured to output large amount of current. This limitation is probably hardware related so there may be nothing you can do about it. Unless there is an option in the BIOS, to configure this port as a regular usb port.

    An external HDD needs at least 0.5 Amps to function and I am thinking that this port does not provide this amount of current. You will need an externally powered HDD if you want it to work with this tablet.
     
  14. aigle

    aigle Registered Member

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    Thanks. That is helpfull.
     
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