How Much Current does a laptop HDD draw?

[d4mo]

I'm looking at getting enclosure for a SATA drive, one that doesn't require power. I may need to run the drive through a USB hub though, and I'm trying to decide if I need a powered hub, or if a unpowered would work. So how much current do they typically draw?

 

[BrightCandle]

The Sata plug specs say about 4.5A for each of 3.3V, 5V and 12V. Xbitlabs did a test in 2007 and determined their drive was less than 3A at 12V and 2A at 5V. I have seen quite a few reviews doing average and peak power draw of drives and they suggest drives at peak never go above 20W total power draw.

 

[d4mo]

I thought USB ports could only source 500mA? How can you run an external SATA on that little of current?

 

[BrightCandle]

You can't. Most HDD to USB adapters I have seen have their own power plug.

 

[mfenn]

Some 2.5" drives will spin up from 1 USB plug, but you often see them come with a (completely standard breaking) Y cable so that they can draw power from two plugs. What does the sticker on your drive say?

 

[ElFenix]

You can't. Most HDD to USB adapters I have seen have their own power plug.

eh? 2.5" drives can be powered by the USB bus alone. i've got one here at work right now. some need to use 2 ports to do it.

 

[Binky]

http://www.silentpcreview.com/article917-page3.html

 

[Eug]

If you get a low power drive, just about any standard in-spec 500 mA USB port can power it. I have four separate 2.5" drives that work just fine off a single 500 mA USB port (2.5 W). However, they're all 5400 rpm low power drives.

A lot of the 7200 rpm drives won't work off just one 500 mA port though. They require too much power. Also, many SSDs require too much power for that too. In fact, some higher power 2.5" drives won't even run reliably off two ports (5 W).

My 4 drives that run off single port USB power:

1) WD My Passport WD5000MEB 500 GB 5400 rpm.
2) Seagate FreeAgent Go 9KW2AL-502 1 TB 5400 rpm.
3) Some 250 GB 5400 rpm drive I pulled out of my Acer laptop and stuck in a Vantec NexStar TX enclosure.
4) Some 160 GB 5400 rpm drive I pulled out of my MacBook Pro and stuck in a Vantec NexStar TX enclosure. I think it's a Seagate with an Apple firmware, but I can't remember.

 

[C1]

Presumably use of a hub implies that it also will be wired off a USB port. In addition, a hub implies that other things might also be plugged into it along with the hard drive. An issue with external dives powered off the buss is length of cabeling. That's why you'll see lots of complaints about too short 1 foot cables being supplied with external enclosures.

I would buy an integrated unit (ie, hard drive and enclosure) advertised to run powered off a USB buss ( http://go.iomega.com/en-us/products...s/prestige/?partner=4760#where_to_buyItem_tab ). In terms of just an enclosure, I like the Sabio ( http://www.tigerdirect.com/applications/SearchTools/search.asp?keywords=sabio+enclosure+2.5" ), but it does run green which some might not like. However, Ive personally found that to only be an advantage with 2.5" drives as they are able to spin up so quick.

 

[PhoenixEnigma]

Powered hub, no question. A standards-compliant unpowered hub won't provide more than one unit of power (100mA for USB 2.0) to a port, regardless of the state of the other ports on the hub. 2.5W is often enough for a 2.5" drive, 0.5W isn't going to be.