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I got eSATA slot in my laptop (HP DV-7) + WD 1TB (The exact model: Caviar Green WD10EADS)

What I want to know, it's if I need something else except from the eSATA cable. Does the eSATA cable provide also power to the HD?

If I'll purchase this cable - do I need something else?


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up vote 21 down vote accepted

The original eSATA specification does not provide power. You'll need a USB cable or wall adapter to power the hard drive. The new eSATAp specification utilizes the USB bus to provide power over one cable, but is relatively rare.

The easiest way to be sure if you have an eSATAp device or not is to check the plug. This helpful image from Wikipedia shows the difference:

eSATA/eSATAp plug difference

The laptop model you listed uses an unpowered eSATA interface and the hard drive you listed is an internal hard drive that uses the original SATA interface, so you will need a cable that accommodates that rather than any plain eSATA cable. While most 3.5" internal hard drives require more power than USB will provide, Western Digital's Caviar Green series reduced power requirements should be met.

They make cables that convert the standard SATA data/power connections to eSATA for data and USB for power (like this example image). However, a far better option IMHO is to buy an external drive enclosure, which is essentially a box you insert your hard drive into with cables provided for USB power and eSATA data. The enclosure will protect your bare drive from damage, and as far as I can tell, aren't that much more expensive than regular cables. If you decide to go that route, make sure the model you buy accepts 3.5 inch SATA hard drives and allows for USB power and eSATA data output. Some models additionally offer USB data connections and/or AC outlet power connections as well.

And here is a eSATAp to SATA+SATA Power so that any standard SATA drive can utilize the power from the eSATAp connection without the need of a USB connection, and only requires the eSATAp connection on the computer end:


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Thanks for your answer, though I'm not sure if I got the eSATAp or the eSATA. It's look like I got the powered one. How can I be sure of this? and eSATAp require special cable as well? – Matan Eldan Apr 5 '11 at 8:36
@Matan: I'm afraid that won't do. I added information about your specific requirements to my answer. – Patches Apr 5 '11 at 9:20
Thank you very much for your help! It seems that I got this eSATAp, and that I only need this cable. I'll try that option first. Thanks again – Matan Eldan Apr 5 '11 at 9:25
A few notes: an eSATAp port is a combination of eSATA and USB. That means any USB device plug will fit and work normally in it. Also note that eSATA ports on desktop PCs are usually unpowered. Laptops have eSATAp ports with the usual USB 5V voltage. There is also a third standard that adds 12V and can so power 3.5 inch drives – David Balažic Nov 8 '13 at 22:09

Quoting Wikipedia

Where a PC-hosted port is concerned, eSATA connectors cannot supply power, and would therefore be more cumbersome to use. Note that this problem has been solved by the introduction of eSATAp.

I guess your external interface comes with power adapter?

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Yes, usually the external enclosure/backplane/array will have its own power cord to power the drive(s) inside of it, and the esata is just for data transfer between the computer and the external enclosure. eSATA was originally used for servers, where you have a seperate backplane with a RAID array of multiple drives, and the esata cable went between it and the server. Usually it'd take a large RAID array to come close to using the full bandwidth of a single sata connection, but you'd need a separate power supply for all those drives in the backplane. – AaronLS Aug 6 '12 at 23:14
Of course, now with SSDs being shock resistant, they are appealing for external drives but need a much faster connection, so eSATAp (see Patches's answer) has begun appearing on consumer devices. – AaronLS Aug 6 '12 at 23:20

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