Author Topic: EEs wanted: will this USB drive work with *this* USB hub?  (Read 2099 times)

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Offline Stupidface

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EEs wanted: will this USB drive work with *this* USB hub?
« on: Mon, 03 January 2022, 08:35:29 »
(NB: If any of the below is unclear, please let me know and I will clarify.)

I recently acquired an 8TB USB 3.0 drive.  In terms of power requirements, the drive is rated (as near as I can make out) at 12V 4A. 

The drive has two FW800 ports on the back; I will be using one of those ports to transfer data.  The drive also comes with a power cable containing a barrel-type connector on one end to plug into the drive and a USB-A plug on the other end to plug into a USB port of some kind for power...which is where the USB hub comes in. 

The particular USB hub I am looking at to do this is described as "a universal AC 100 240 V to DC 5V 6A with 6 USB Ports Power Supply."  The 6 USB ports are connected in parallel so the amps will be divided according the number of charging devices I plug in.  I plan on plugging in two devices (a smartphone and the aforementioned USB drive), so presumably each USB port will be able to provide 3 amps.

ETA - For the sake of anyone faced with a similar problem in the future, this matter hangs on the following formula:

W = V * A (or: watts equals volts multiplied by amps)

In this case, we have a hard drive with a power supply drawing 12 volts at 4 amps, so: 12V * 4A = 48 Watts

Meanwhile, as suicidal_orange points out, the USB hub supplies 5 volts at 6 amps so: 5V * 6A = 30 Watts.

Bottom line: Plugging a 48 Watt device into a 30 Watt hub and expecting it to operate is not likely to meet with much success.


(Well, now I know.)
« Last Edit: Tue, 04 January 2022, 05:08:03 by Stupidface »

Offline suicidal_orange

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Re: EEs wanted: will this USB drive work with *this* USB hub?
« Reply #1 on: Mon, 03 January 2022, 09:38:03 »
USB 3 has a spec for power delivery which allows for up to 240W, your drive (if you guessed right) requires 12V@4A which is only 48W so that's how the supplied cable should be used.

That hub provides 5V@6A which is only 30W and that's before the phone steals any and some is lost in the voltage conversion so if everything you said is accurate it wont work.
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Offline Darthbaggins

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Re: EEs wanted: will this USB drive work with *this* USB hub?
« Reply #2 on: Mon, 03 January 2022, 14:48:30 »
Straight nope, it wont be a stable power source.  (As S.Orange already stated as well)

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Offline Stupidface

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Re: EEs wanted: will this USB drive work with *this* USB hub?
« Reply #3 on: Tue, 04 January 2022, 05:18:59 »
USB 3 has a spec for power delivery which allows for up to 240W, your drive (if you guessed right) requires 12V@4A which is only 48W so that's how the supplied cable should be used.

Yes, and therein lies the problem: the laptop I would like to use this drive with only has USB 2.0 ports, hence my messing around with USB 3.0 hubs.  Unfortunately, as I have quickly learned, many of the USB 3.0 hubs for sale are not meant to power anything substantial (like, say, a HD drawing 48 Watts). 

That hub provides 5V@6A which is only 30W and that's before the phone steals any and some is lost in the voltage conversion so if everything you said is accurate it wont work.

Indeed, I was barking up the wrong tree with this one.  Thank you for taking the time to sort me out. [tips hat]




« Last Edit: Tue, 04 January 2022, 05:37:49 by Stupidface »

Offline Stupidface

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Re: EEs wanted: will this USB drive work with *this* USB hub?
« Reply #4 on: Tue, 04 January 2022, 05:35:32 »
Straight nope, it wont be a stable power source.  (As S.Orange already stated as well)

Thank you for confirming suicidal_orange's answer.  This one was a no-hoper, all right.