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    Self-powered USB hub and power supply adapter ampere capacity

    Discussion in 'Accessories' started by Freakish, Mar 14, 2010.

  1. Freakish

    Freakish Notebook Geek

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    I am looking for a power supply adapter for my USB Hub so it can support at least 2 bus-powered external hard drives. The hub's rating is 5 volts, 2 amperes.

    I would like to know if it would be OK to buy a power supply adapter rated at less than 2A. I've been looking for power supply adapters and the ones that do support 2A are more expensive (more expensive than the USB hub itself) compared to those that support less than 2A.

    Will a power supply adapter that supports less than 2A (~1-1.5A) work fine to support two external hard drives?

    The external hard drives are both bus-powered Western Digital My Passport Essentials 250 GB. The OS is Windows XP SP3.
     
    Freakish, Mar 14, 2010
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  2. Greg

    Greg Notebook Nobel Laureate

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    You'll be cutting it really close if you do not go with a 2A PSU. 1A is definitely not enough, 1.5A is pushing your luck.
     
    Greg, Mar 14, 2010
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  3. Vogelbung

    Vogelbung I R Judgemental

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    Depends on the enclosure - in terms of how much current the enclosure + drive needs to start up. Technically speaking the maximum current draw of a USB device should be 500ma, but many bus-powered drives momentarily demand higher when starting up - one the main reasons why some drives 'hunt' when plugged into an otherwise plausibly-powered hub.

    For that reason really, you should be looking for about a 2.5A-rated supply to power two HDD's with zero hassle. Failing that, stick with 2A.
     
    Vogelbung, Mar 14, 2010
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