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.
http://www.sednacomputer.com/products/se-c-poesata-1m.html
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.
P1 5V
P4 GND
P12 12V
P13 GND
http://www.addonics.com/technologies/euhp.php
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.
HTH,
Paul