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- Sata computer cable.
- Peter Jason
November 5, 2015, 2:24 am
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This one is the USB3 version, but there seems no power connection.
Does the power come with the USB3?
The USB2 type comes as "eSata" with a power connection:
and I'm using this now.
Can I just use the USB3 type instead?
Re: Sata computer cable.
Peter Jason wrote:
The first cable is intended for 2.5" (5V only) laptop
SATA drives. USB3 has 5V on the cable as the "bus voltage".
And a hard drive can be powered from that, up to the USB3
current limit. USB3 is preferred for this, since USB3
allows a bit more current than USB2 does (from a
specification point of view). And if you use this
cable with a 3.5" hard drive, there would be no 12V
to power the spindle motor.
Inside the SATA connector end, would be a USB to SATA
converter chip. But there would not be room nor power,
to convert 5V to make 12V @ 3A. And while USB3 promises
up to 100W in some future incarnation, I'm not sure
that anyone offers a hardware solution doing that today.
All we can assume is 5V at slightly less than an amp.
And that's not enough to spin up a 3.5" drive.
The second cable is an ESATAp, with the power contacts.
It depends on the characteristics of the disk controller
card with the ESATA connector on it, as to what voltage
or voltages are available. The lack of standards here,
makes me just a bit concerned about the scheme.
The best reference I've been able to find in the past
is this. The text says that a "12V EUHP" has both
12V and 5V on it. My guess is, the 5V comes from the
USB pin section (so only a hybrid connector, and not
just an ESATAp with power pins added is needed), while
the P12 and P13 provide the 12V rail needed by a 3.5" drive.
The number of grounds should be equal to the number of
supply pins, so the ground contacts don't burn from
too much current flow.
The early ESATAp I saw, didn't have USB contacts,
and it was unclear exactly what was going on with
P12 and P13. And it's important to understand
that stuff, to connect compatible ESATA controller
cards to enclosures and so on. While I've tried
looking for this topic before on this site,
I'm still not getting a strong feeling they're
on top of things. I don't know who is in
charge of certifying compatible solutions.
When I clicked on the link to get the PDF spec,
I got a 404 error.
site:sata-io.org esata power
So if your stuff works, great, good choice :-)
If it doesn't work, I don't have a good reference
for why it doesn't work.
Re: Sata computer cable.
I have been using one of the eSata USB2 cables for about 3 years on a
SSD and HDDs. It's very convenient to do this. I'm thinking of
getting rid of all those technicolored molex cables and those ribbon
data cables and just using the eSata ones. This will make
connections easier and remove the tangle inside the case.
I made the mistake of using the old type of case where the HDD bays
are facing the motherboard because this makes it very difficult to
remove the drives without crashing into the motherboard and assorted
cables. Some better cases have the bays at 90degrees to this so the
drives can be removed easily.
See the tangle!