power issues on the western digital passport

rookie1010 · 08-05-2009, 01:49 AM

Hello,

I was interested in buying the Western Digital My Passport Essential 250GB USB Portable External Hard Drive (http://www.amazon.co.uk/Western-Digi...9455038&sr=8-3).

I read that the drive may have issues with USB 2 ports with 500mA ratings as it requires 1000mA and that one can get an optional cable in case it does not work.

Looked around and came across the following cable "12V Western Digital My Book Essential Ed. power supply adaptor", is this the external cable that goes with the drive?

http://www.amazon.co.uk/Western-Digi...9457908&sr=1-1

p.s. would you guys recommend this drive or would you recommend another drive which would work with 500mA usb2 ports

**raptor_pa** · 08-05-2009, 05:29 AM

No that is the 3.5 inch disk power supply. Are you maybe referring to the cable with the second USB connector for power only? This allows yo to plug into two USB ports on your machine, one for data/power and one for power only, at the same time. http://eshop.macsales.com/search/OWC...in+Mini+B+Cabl A lot of the drives that are supposed to work with 500 mA ports don't, until you try it it's hard to say. I have seen some work, another one same model, purchased same time would not work.

rookie1010 · 08-05-2009, 06:54 AM

thanks for the reply,

yes, i am referring to the cable with the second USB connector for power onlyi think i will give these drives a miss and go for a regular harddrive for the moment.

why are these internal hard drives made with higher current requirements 1000mA?
i have checked my mac and the usb's on it have a current rating of 500mA, even the usb specification states the same.

are there any portable usb hard drives with 500 mA current ratings? does the 2usb type B connector going into a usb type A connector work with no issues?

**raptor_pa** · 08-05-2009, 07:39 AM

It genrally works, I have seen it miss on occasion, the USB may not have quite 500 mA. In order for the drives to function, they need a inimum amount of current. As capacities increase, that current becomes higher ( more platter to spin , higher tolerances etc. So manufacturers are faced with two issues, not just how to fit more data into the same space on one platter, but how to keep the number of platters to a minimum andhow to keep current reuirements down. USB drives are just normal hard drives in a USB enclosure. I've always personally thought of them as an afterthought, Hey we can seel more drives! Other than portable or backup storage, an internal drive will always perform faster and more reliably.

rookie1010 · 08-05-2009, 10:49 AM

thanks for the reply,

why then use usb to power it if usb does not provide that much juice? why not provide the optional power adaptor with instructions on how to get the juice out?

i guess there are not any portable usb hard drives with 500 mA current ratings going by the capacity of current usb drives? does the 2usb type B connector going into a usb type A connector work with no issues?

**raptor_pa** · 08-05-2009, 10:59 AM

Ummm B will not even physically fit into a type. Not sure what the question is. The Power Y cable has two A connectors and then the other end would have to be the one for the device. USB was not designed to support Hard drives specifically, it is Universal. 3.5 inch HDs need the external because they need 12VDC, 2.5 inch drives, it works on some not on others. The concept of powering from USB is strictly for portability, if I have my laptop on battery, I can attach my external drive and need no access to AC line voltage to power either device. USB hard drives are not a simple replacement for an internal drive when it comes to reliability, or prformance. They are portable storage, or occasional backups. They seem to suffer more heat related failures than internal drives, data rates are slower, and they are more susceptible to shock damage.

nugge · 08-05-2009, 11:42 AM

Quote:

Originally Posted by raptor_pa

Ummm B will not even physically fit into a type. Not sure what the question is. The Power Y cable has two A connectors and then the other end would have to be the one for the device. USB was not designed to support Hard drives specifically, it is Universal. 3.5 inch HDs need the external because they need 12VDC, 2.5 inch drives, it works on some not on others. The concept of powering from USB is strictly for portability, if I have my laptop on battery, I can attach my external drive and need no access to AC line voltage to power either device. USB hard drives are not a simple replacement for an internal drive when it comes to reliability, or prformance. They are portable storage, or occasional backups. They seem to suffer more heat related failures than internal drives, data rates are slower, and they are more susceptible to shock damage.

Hi.
Actually they need the added 500mA becose it is 500mA + 500mA = 1A. This is still at 5V NOT 12V. As all normal 2.5" laptop hard drives are 5V and thus also the drive in a portable 2.5" is 5V I have not seen any failures on using 2 USB to power 1 Device. Only if the cable would have been damaged could there be a problem.

Some raid 2.5" server harddrives use 12V.

//nugge

rookie1010 · 08-05-2009, 11:56 AM

thanks for the replies,

my question was does the strategy of the y cable work with no issues.
with one type-A providing data+power and the other usb type-a provoding power

**raptor_pa** · 08-05-2009, 12:05 PM

I won't say with no issues, because it is dependent on a lot of variables. I have ahd good success witht he portable I carrry, but if I use it once every coule of weeks I'd be surprised. Without the Y cable, I have about a 50-50 chance of maintaining operation. I've had a the same drive and cable on another laptop and it would still drop out, so it's not a perfect fix. The specs call for 500 mA on a USB port, but other devices pll current, a mouse will pull about 100 mA not sure of keyboard so the number of devices on the 5VDC bus that powers the USB willaffect the amount of current available at any given time. Best answers is in my experience, it is much beter with the Y cable, but not perfect.

nugge · 08-05-2009, 12:31 PM

Quote:

Originally Posted by rookie1010

thanks for the replies,

my question was does the strategy of the y cable work with no issues.
with one type-A providing data+power and the other usb type-a provoding power

Yes it will work.

rookie1010 · 08-05-2009, 02:06 PM

thanks for the reply and demystifying the y cable issue.

08-05-2009, 01:49 AM	#1 (permalink)
rookie1010 Registered User Join Date: Aug 2009 Posts: 5 OS: windows xp	power issues on the western digital passport Hello, I was interested in buying the Western Digital My Passport Essential 250GB USB Portable External Hard Drive (http://www.amazon.co.uk/Western-Digi...9455038&sr=8-3). I read that the drive may have issues with USB 2 ports with 500mA ratings as it requires 1000mA and that one can get an optional cable in case it does not work. Looked around and came across the following cable "12V Western Digital My Book Essential Ed. power supply adaptor", is this the external cable that goes with the drive? http://www.amazon.co.uk/Western-Digi...9457908&sr=1-1 p.s. would you guys recommend this drive or would you recommend another drive which would work with 500mA usb2 ports Last edited by rookie1010; 08-05-2009 at 01:52 AM.

08-05-2009, 05:29 AM	#2 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,786 OS: XP	Re: power issues on the western digital passport No that is the 3.5 inch disk power supply. Are you maybe referring to the cable with the second USB connector for power only? This allows yo to plug into two USB ports on your machine, one for data/power and one for power only, at the same time. http://eshop.macsales.com/search/OWC...in+Mini+B+Cabl A lot of the drives that are supposed to work with 500 mA ports don't, until you try it it's hard to say. I have seen some work, another one same model, purchased same time would not work. __________________ Last edited by raptor_pa; 08-05-2009 at 05:30 AM.

08-05-2009, 06:54 AM	#3 (permalink)
rookie1010 Registered User Join Date: Aug 2009 Posts: 5 OS: windows xp	Re: power issues on the western digital passport thanks for the reply, yes, i am referring to the cable with the second USB connector for power onlyi think i will give these drives a miss and go for a regular harddrive for the moment. why are these internal hard drives made with higher current requirements 1000mA? i have checked my mac and the usb's on it have a current rating of 500mA, even the usb specification states the same. are there any portable usb hard drives with 500 mA current ratings? does the 2usb type B connector going into a usb type A connector work with no issues?

08-05-2009, 07:39 AM	#4 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,786 OS: XP	Re: power issues on the western digital passport It genrally works, I have seen it miss on occasion, the USB may not have quite 500 mA. In order for the drives to function, they need a inimum amount of current. As capacities increase, that current becomes higher ( more platter to spin , higher tolerances etc. So manufacturers are faced with two issues, not just how to fit more data into the same space on one platter, but how to keep the number of platters to a minimum andhow to keep current reuirements down. USB drives are just normal hard drives in a USB enclosure. I've always personally thought of them as an afterthought, Hey we can seel more drives! Other than portable or backup storage, an internal drive will always perform faster and more reliably. __________________

08-05-2009, 10:49 AM	#5 (permalink)
rookie1010 Registered User Join Date: Aug 2009 Posts: 5 OS: windows xp	Re: power issues on the western digital passport thanks for the reply, why then use usb to power it if usb does not provide that much juice? why not provide the optional power adaptor with instructions on how to get the juice out? i guess there are not any portable usb hard drives with 500 mA current ratings going by the capacity of current usb drives? does the 2usb type B connector going into a usb type A connector work with no issues?

08-05-2009, 10:59 AM	#6 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,786 OS: XP	Re: power issues on the western digital passport Ummm B will not even physically fit into a type. Not sure what the question is. The Power Y cable has two A connectors and then the other end would have to be the one for the device. USB was not designed to support Hard drives specifically, it is Universal. 3.5 inch HDs need the external because they need 12VDC, 2.5 inch drives, it works on some not on others. The concept of powering from USB is strictly for portability, if I have my laptop on battery, I can attach my external drive and need no access to AC line voltage to power either device. USB hard drives are not a simple replacement for an internal drive when it comes to reliability, or prformance. They are portable storage, or occasional backups. They seem to suffer more heat related failures than internal drives, data rates are slower, and they are more susceptible to shock damage. __________________

08-05-2009, 11:56 AM	#8 (permalink)
rookie1010 Registered User Join Date: Aug 2009 Posts: 5 OS: windows xp	Re: power issues on the western digital passport thanks for the replies, my question was does the strategy of the y cable work with no issues. with one type-A providing data+power and the other usb type-a provoding power

08-05-2009, 12:05 PM	#9 (permalink)
raptor_pa Mod Hardware Team Join Date: Dec 2008 Location: Central PA Posts: 4,786 OS: XP	Re: power issues on the western digital passport I won't say with no issues, because it is dependent on a lot of variables. I have ahd good success witht he portable I carrry, but if I use it once every coule of weeks I'd be surprised. Without the Y cable, I have about a 50-50 chance of maintaining operation. I've had a the same drive and cable on another laptop and it would still drop out, so it's not a perfect fix. The specs call for 500 mA on a USB port, but other devices pll current, a mouse will pull about 100 mA not sure of keyboard so the number of devices on the 5VDC bus that powers the USB willaffect the amount of current available at any given time. Best answers is in my experience, it is much beter with the Y cable, but not perfect. __________________

08-05-2009, 02:06 PM	#11 (permalink)
rookie1010 Registered User Join Date: Aug 2009 Posts: 5 OS: windows xp	Re: power issues on the western digital passport thanks for the reply and demystifying the y cable issue.