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    Powered USB Hubs

    Discussion in 'Accessories' started by built, Feb 14, 2009.

  1. built

    built Notebook Deity

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    Can I use a powered USB hub without using the AC adapter if each of the components attached to the USB hub has its own power supply.

    I have two Cyberpower USB 7 port hubs, and I would like to use them unpowered so that my WD My Book externals power down with my computer. It seems when I use a powered hub, and use the AC adapter, the My Book externals (both Home and Essential) do not power down automatically and I have to unplug them.

    So, can I simply use this powered hub without power since all of the components have their own AC supply?
     
    built, Feb 14, 2009
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  2. FrankTabletuser

    FrankTabletuser Notebook Evangelist

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    Yes.

    You only need a power supply for your HUB if the connected devices need more than 500mA, but because your devices are all powered by their own power supply they don't consume any power from your HUB.
     
    FrankTabletuser, Feb 14, 2009
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  3. ekincam

    ekincam Notebook Enthusiast

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    It depends on the USB hub. I have one that doesn't work without being plugged in.
     
    ekincam, Feb 14, 2009
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  4. DetlevCM

    DetlevCM Notebook Nobel Laureate

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    I think my Belkin Hubs don't work without the power supply...

    But speaking about external HDD powering down - mine do, and they are connected to powered USB Hubs.

    However: Only NTFS drives can power down it seems.
    (some drives come pre formatted in FAT32 - even 250GB ones...)
     
    DetlevCM, Feb 15, 2009
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  5. built

    built Notebook Deity

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    Hey everybody...

    THANKS for the great responses.

    I have a Cyberpower 7 port USB hub ( https://shop3.frys.com/product/5665801?site=sr:SEARCH:MAIN_RSLT_PG ) and based on the advice you guys gave me, I tried to use it without power.

    So far so good. It is working great. The hub itself seems to draw power from the computer, but I am imagining that, as others have said, the components themselves (ie external hard drives) are using their own power through their own AC adapters, and not through their USBs.

    For some reason, the WD drives were not powering down when the hub was powered. I read somewhere that it was because the drive was powered and still delivering some power through the USB ports even though, ostensibly, USB power should not be sufficient to spin up a 3.5 1TB drive (or so I thought).

    I had reformatted all my drives to NTFS as soon as I got them but still they would not power down with the computer. Now they power down as intended.

    Very odd. Maybe somebody else knows why.

    Thanks again everybody!
     
    built, Feb 15, 2009
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