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Your USB device has exceeded the power limits...

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September 6, 2007 5:31:08 AM

I bought a http://www.newegg.com/Product/Product.aspx?Item=N82E16817163050 for my dead dell laptop's 60GB 4200rpm Hitachi Hard Drive, and its directly plugged into my other laptop -
Quote:
A USB device has malfunctioned and exceeded the power limit of its port. ...


Just for confirmation (have much sensitive data on it, I usually don't ask such basic questions XX) - This means I have to plug it into a real desktop....right?...not another fricken powersaver laptop...

Oh yes, the drive is powered through usb, not some external cable..
September 6, 2007 7:04:57 AM

USB devices are allowed to pull up to 400mA for each port. Unfortunately if you have a keyboard with the handy USB ports on it and you plug in your memory stick, you still are left with 400mA for your keyboard AND USB stick COMBINED. The keyboard will draw it's power from the USB port on the computer, so unless you have a device that has it's own power source, each port on your computer can draw no more than 400mA. You could try a desktop, but laptops and desktops have the same 400mA requirement.

When you buy one of those enclosures where you add your own hard drive, you run this risk. The company that makes the enclosure knows they can't draw more than 400mA of power. They decide on how much power they want to use for their controller, and how much for the hard drive. Unfortunately if they assume they can use 100mA, but your hard drive doesn't use 300mA and instead 350mA then you'll get this problem.
You bought what IMO is an 'no name POC'. Check this site out:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

If you look at the picture #3 you have a power connector and a USB port. I know this one has fingerprint stuff, but I grabbed it because it was the fastest and I should be asleep. Normally you'd plug in your USB port to the computer and be set. But if you were one of those very lucky souls that ended up with a hard drive that's not very power efficient and draws alot of power, then you use the second cable that comes with it and plug it into the power connector. Viola! You now have 800mA of power from 2 USB ports and you'll have PLENTY of power for your device.

Really you have 2 options. Get a new hard drive, or get a new enclosure. You might have a computer that is a little more lax on the 400mA requirement, but I'm sure you don't want to use your hard drive 'on the rare computer that it works on'. Just get yourself a better quality enclosure that has the USB port and the power connector and you'll be set. Worst case with this setup you'll have to use 2 cables instead of 1 for your external drive.

Don't worry. Your data is safe. Just get yourself a better enclosure and you'll be set.

Good luck :) 
September 6, 2007 9:08:59 AM

Get a powered USB hub.
Related resources
September 7, 2007 3:13:15 AM

Yeah.. get one of those and you'll be set ;) .
a b D Laptop
a c 152 G Storage
September 7, 2007 4:09:06 AM

400 mA.... its 500 per port. thats why they give you the y-cable to use 2 usb ports to get 1000 mA(1 Amp)


Did you plug it into 2 usb ports on the computer(notebook)?

I know i have run 1100 mA off a single port on both my laptop and desktop :) 
September 7, 2007 5:57:57 AM

I just did a search around for the USB requirements. Here's a few links...

http://www.maxim-ic.com/appnotes.cfm/an_pk/3241

http://talkback.zdnet.com/5208-10741-0.html?forumID=1&t...

http://en.wikipedia.org/wiki/USB

http://www.usb.org/developers/usbfaq/#pow1

I guess somewhere I got 400 in my head instead of 500. I'm thinking that way back in the day with USB 1.1 some computers had 1 USB port on what was basically a 4 port USB powered hub giving you 400mA total. These were usually REALLY crappy machines to begin with and this was an easy way to have 4 USB ports with only 1 signal connection on the motherboard. I stand corrected on 500mA :) .

Now i'm just a little curious. What device did you have that pulled 1100mA? I don't really see how that's possible since the device has to 'request' the mA it needs, but it can't ask for more than 5 units of power. I do remember I had something that wanted more power than was available, and on the same screen you have your screenshot we could see for about 1/2 second it wanted more than what was available. I don't remember the numbers or even what device it was. I just remember seeing it and wondering what the heck it meant for the device we were trying to use.
a b D Laptop
a c 152 G Storage
September 7, 2007 6:12:51 AM

Ok well i guess i cheated to get 1100.

i was running a usb to ide adapter

Like this but from ncix.com

It always tells the computer 500 mA. But i was running an old(i mean old) laptop drive that had a rating on 1.1Amps(or was it 1.2A). Either way it worked :) 
I had to try it on my laptop and it worked there too.

So the port powered the device and the drive.

Not that I recommend this and thats why they make usb Y cables to let you double up the current.

Also all those usb fans, glowy mouse pads and laptop coolers.... those don't tell the port how much power. they just take the 5 volts and run with it(there is a auto resetting fuse on the board to prevent excessive power drain and damage to the board, but its not under 1100 :)  ). that's how i charge my mp3 player with the PC off too.
September 7, 2007 6:19:20 AM

Hahaha. That's funny stuff. I'm wondering if the rated was actually what it would draw at max load, or if that was max load + a fudge factor. That's very interesting though. I am quite impressed that you caught the 400mA mistake. Not many people are that technical savy on information that's almost pointless. Who really cares if its 400mA or 500mA? All that matters is it draws 'too much' or it works ;)  Good job on catching that though. I'll have to keep my eye out for your comments.
September 7, 2007 11:00:49 PM

OK - guys - the Y cable with both connected works now! (wonder why I didn't try that...sigh..I guess experience is still what makes a tomshardware veteran.. :heink:  )

(I'm one of the very few young ones here (14) BTW...hope that makes up for my lack of experience!)

Oh yeah.... I can't seem to access anything......random files,can'tgo into myadmin in documents and settings..'

can I direct boot off this drive or something in bios config?
a b D Laptop
a c 152 G Storage
September 8, 2007 12:29:02 AM

some boards let you boot off of it[USB]...

By cant access files do you mean NTFS security(made your files private did you??) is stopping you?

If so right click the drive and take ownership of the thing...this will take a while but you will be able to access all

Steps to take ownership of files.

Right click the drive you want to take ownership of and click properties.

Get over to the "Security" Tab and click on "Advanced".
Once there click on the "Owner" tab(Note the current owner of this item, if its all messed like in my screen, it's a user from the original computer).
Select your self from the list of owners(Change owner to).
Make sure you select "Replace owner on subcontainers and objects". hit "Apply"

You should get what looks like a file copy box but its called Security and it will take ownership of everything. This can take some time


Hope that helps some

@ cyberjock - That rating is the power(MAX. i guess about 700 once running) needed to get that thing spinning. its is like 3 times thicker then a notebook drive now days...
a b G Storage
September 8, 2007 1:37:15 AM

I got that same adapter also, but it's from Bytecc and it works great.
Those external cases sux! Got like 6 different ones and they all died on me
spent like over a total of $200 and 2 almost fried my HDs!

a b D Laptop
a c 152 G Storage
September 9, 2007 2:28:25 AM

mine is bytecc(don't know why i was thinking ngear..but it's bytecc cause i also have an enclosure from them too..for my dad) too....

@ DeusEx - you got it going?
a b G Storage
September 9, 2007 2:56:04 AM

haha i have a few of those sitting around, never seen a laptop drive function off em, had to use a converter that added power :/ 

nukemaster said:
Ok well i guess i cheated to get 1100.

i was running a usb to ide adapter
http://www.comtronics.co.uk/images/ProductPic/USB%20IDE.jpg
Like this but from ncix.com

It always tells the computer 500 mA. But i was running an old(i mean old) laptop drive that had a rating on 1.1Amps(or was it 1.2A). Either way it worked :) 
I had to try it on my laptop and it worked there too.

So the port powered the device and the drive.

Not that I recommend this and thats why they make usb Y cables to let you double up the current.

Also all those usb fans, glowy mouse pads and laptop coolers.... those don't tell the port how much power. they just take the 5 volts and run with it(there is a auto resetting fuse on the board to prevent excessive power drain and damage to the board, but its not under 1100 :)  ). that's how i charge my mp3 player with the PC off too.

January 27, 2009 8:51:46 AM

If you got a message complaining about "the usb hub has exceeded the power limit" or something like that, just get yourselve a different good usb cable. I got this issue myself and replaced a better cable and it works fine.
June 6, 2011 8:49:41 AM

cyberjock said:
USB devices are allowed to pull up to 400mA for each port. Unfortunately if you have a keyboard with the handy USB ports on it and you plug in your memory stick, you still are left with 400mA for your keyboard AND USB stick COMBINED. The keyboard will draw it's power from the USB port on the computer, so unless you have a device that has it's own power source, each port on your computer can draw no more than 400mA. You could try a desktop, but laptops and desktops have the same 400mA requirement.

When you buy one of those enclosures where you add your own hard drive, you run this risk. The company that makes the enclosure knows they can't draw more than 400mA of power. They decide on how much power they want to use for their controller, and how much for the hard drive. Unfortunately if they assume they can use 100mA, but your hard drive doesn't use 300mA and instead 350mA then you'll get this problem.
You bought what IMO is an 'no name POC'. Check this site out:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

If you look at the picture #3 you have a power connector and a USB port. I know this one has fingerprint stuff, but I grabbed it because it was the fastest and I should be asleep. Normally you'd plug in your USB port to the computer and be set. But if you were one of those very lucky souls that ended up with a hard drive that's not very power efficient and draws alot of power, then you use the second cable that comes with it and plug it into the power connector. Viola! You now have 800mA of power from 2 USB ports and you'll have PLENTY of power for your device.

Really you have 2 options. Get a new hard drive, or get a new enclosure. You might have a computer that is a little more lax on the 400mA requirement, but I'm sure you don't want to use your hard drive 'on the rare computer that it works on'. Just get yourself a better quality enclosure that has the USB port and the power connector and you'll be set. Worst case with this setup you'll have to use 2 cables instead of 1 for your external drive.

Don't worry. Your data is safe. Just get yourself a better enclosure and you'll be set.

Good luck :) 



HI this answer makes sense i am haveing the same problem would that also fix the fact that this hard drive will now not work on my WD Media Player it wont recognise it... can you please help i am very desperate!!
June 6, 2011 8:52:43 AM

cyberjock said:
USB devices are allowed to pull up to 400mA for each port. Unfortunately if you have a keyboard with the handy USB ports on it and you plug in your memory stick, you still are left with 400mA for your keyboard AND USB stick COMBINED. The keyboard will draw it's power from the USB port on the computer, so unless you have a device that has it's own power source, each port on your computer can draw no more than 400mA. You could try a desktop, but laptops and desktops have the same 400mA requirement.

When you buy one of those enclosures where you add your own hard drive, you run this risk. The company that makes the enclosure knows they can't draw more than 400mA of power. They decide on how much power they want to use for their controller, and how much for the hard drive. Unfortunately if they assume they can use 100mA, but your hard drive doesn't use 300mA and instead 350mA then you'll get this problem.
You bought what IMO is an 'no name POC'. Check this site out:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...

If you look at the picture #3 you have a power connector and a USB port. I know this one has fingerprint stuff, but I grabbed it because it was the fastest and I should be asleep. Normally you'd plug in your USB port to the computer and be set. But if you were one of those very lucky souls that ended up with a hard drive that's not very power efficient and draws alot of power, then you use the second cable that comes with it and plug it into the power connector. Viola! You now have 800mA of power from 2 USB ports and you'll have PLENTY of power for your device.

Really you have 2 options. Get a new hard drive, or get a new enclosure. You might have a computer that is a little more lax on the 400mA requirement, but I'm sure you don't want to use your hard drive 'on the rare computer that it works on'. Just get yourself a better quality enclosure that has the USB port and the power connector and you'll be set. Worst case with this setup you'll have to use 2 cables instead of 1 for your external drive.

Don't worry. Your data is safe. Just get yourself a better enclosure and you'll be set.

Good luck :) 



Hi i too have the same problem would this fix the fact that my WD Media player does not recognise the harddrive...I have all these movies and i am unable to view...was fine a few days ago now all of a sudden it wont...I am desperate thanks in advance
June 9, 2011 12:31:38 PM

I changed my USB cable and it worked thanks heaps deals2bid!!!
!