2.5" external hdd, usb only power?

So pretty much every 2.5" hdd outthere that you buy as an external drive, will power off only the usb plug. I've bought two 2.5" sata hdds in the past year, and bought my own external enclosures for them, because i wanted esata and didnt wanna pay for a prebuilt one.

In the first one, I figured it was because the case was cheap, and maybe the fact that there was esata it needed power form the DC input (from an extra usb plug). Now I got a second hdd (WD 7200 320g), and im having the same issue.

I got a different enclosure, not from some random brand like before(thermaltake this time). Am I just getting bad enclosures that cant route power from the usb connector correctly? Or do all 2.5 esata enclosures need an external power source to power up? I've tried powering it from my laptop, and external powered usb hub. But all it does it click, and not power up like its underpowered.

I think it just sucks, that by spending the extra time getting something custom, rather then just buying it, I cant have the same functionality as if i bought it from the store. Instead I have to waste an extra usb port just to power up the hdd, and carry around extra cables all the time.

Would a simple usb passthrough be all i need to power them both from one usb port? If so where do you buy em, cause id rather not deal with ebay for like a 1$ usb thing, and get it shipped to canada for 15$.

Thanks for reading, and for any help.

 

That's odd. 2.5" HDD's require 5v... and coincidentally that's just what a USB port puts out... I understand that sometimes on smaller laptops or if you are on battery power the USB port may not be able to fully power the peripheral, but I have never had this issue personally. Since it sounds like you have used all of the possible combinations maybe it's your laptop? have you tried plugging this into a different computer?

 

Yea, i think(not sure) they did the same thing with other laptops, although i might have just told the other people, to use both usb ports, because i thought it wouldnt work otherwise.

I should try another computer, but i figured a usb hub thats powered, should power it and atleast spin it up. Weird..

 

are you always trying 7200rpm drives? That may be the issue, i have a vantec esata that needs only 1 usb (using 5400.3 160GB internally). I also have a 320gb 5400.5 in a coolmax case that uses only 1 usb (no esata though). Some 7200rpm drives need more than 500ma on startup. I'm sure if you went with 2 usb power connections, it would work.

 

The first drive that i tried was a 5400rpm. I guess i can try swapping out the cases, and seeing if that makes a difference.

Thats intersting what you said about maybe it needed more power to spin up. So i tried getting it spun up first by having both plugged in, then taking out the DC power, and only have usb, but that didnt work either.

I'm beginning to think that these esata enclosures are ONLY drawing power from the DC port, and not the usb port.

 

I've got USB/eSATA enclousure, and I've got a 100GB 7200rpm HDD in it.

It works on the USB connection only, as it powers from there and uses the USB to transfer the information. And limits the data at about 30MB/s of course.

The eSATA port however does not have power input, so the encousure uses the DC in port for that purpose. Now I can bring power to the DC in port via USB cable (has cable with two USBs on one side and DC on other side), or I can connect external power adaptor to it (5V, 500mA min).

I'm not sure if the DC in port and the USB port on the encousure are connected internally though .. I think not. Because otherwise one could connect to the USB port to power the eSATA port, but then the computer should be told somehow which one to use for data - the USB or the eSATA

I haven't used mine for eSATA yet, just the USB

 

I haven't much experience with esata enclosures, only my vantec.
It will power the drive through USB only, independent of whether I am using USB or eSATA for transferring.

 

As already noted, eSATA is only data and not power, so it is necessary to use a power connector. The USB specification provides for 500mA current per port. That is 2.5W at 5V. You will see from Tom's Hardware that the majority of the 2.5" HDDs they have tested have a maximum power consumption greater than 2.5W.

The fact that most people are able to run 2.5" from a single USB port indicates that there is, on most notebooks, some flexibility in the maximum power that can be drawn from one port. However, some computers are less generous, which is why enclosure manufacturers usually make provision for using a second USB port for extra power.

John

 

So you can get eSATA-speed when powered through USB while using the eSATA?

 

Yes. Through USB, the max i hit was approx 30mb/sec. Using eSATA, it was over 40mb/sec.

 

So 40MB/s with eSATA powered through USB?

Then i guess some enclosures can handle power through USB and then connect via eSATA at the same time.

 

With eSATA you get the same HDD performance as if the HDD was mounted internally. The first pair of HDTune results in this thread are with the HDD in an external enclosure.

Until such time as manufacturers produce a combo USB (for power) / eSATA cable which will connect to the combo USB / eSATA ports provided in some notebooks it will be necessary to connect to a USB port to get the power.

Most of the enclosures with eSATA also have a USB port that can be used for data transfer if eSATA is not available.

John

 

I think the issue is that the cases ive bought so far, are made that they dont power up when just using the usb connection. Thats just a lazy company, or maybe theyre trying to cover themselves incase a user uses the DC input and the usb port at the same time. Either way, there should be some checking inplace or something to make it possible.

I guess the only solution, is to buy a case that I know will power using the usb connection. Since its not obvious on boxes(or a usb/esata switch doesnt do it), ill have to research it online. But I wont be buying any more enclosures anytime soon, ill just live with it. It doesnt really affect me that often, only if someone else wanted to use my drive and doesnt have an esata port. too bad for them, theyll just have to use two of their usb slots.