# External HDD with dual head USB cable



## Jerold (Jun 23, 2004)

I've asked about this on another thread of mine,but it has been awhile and I finally got the dual head USB cable for my 2.5" 80GB external HDD. I got the cable from www.cooldrives.com her is the link to it - 
http://www.cooldrives.com/usb-power-cable-mini-b.html

When I plug it into the USB2 ports on my laptop, it still won't power up the HDD. Is the dual head not providing enough power for this HDD?
I don't have any other devices that use a mini B USB connctor to test the unit out on. I chose this cable option instead of the USB power cable that plugs into the DC plug of the HDD enclosure so I cna cut down on the number of cables I need to carry when I travel.

Any Ideas?


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## ~Candy~ (Jan 27, 2001)

I'd be surprised if you got a USB hard drive without it's own power source to work on your laptop.


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## JohnWill (Oct 19, 2002)

Candy, I use both of my 2.5" drives with no extra power on my laptop. Both of them have a dual-headed USB cable, the second USB connection is just to double the power available to the drive.


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## Jerold (Jun 23, 2004)

I got my HDD enclosure from the same company - cooldrives.com and the HDD is an IBM/Hitachi Travelstar 80GB 2.5" drive. I just got the Firewire cable and the USB cable. No power cable. I have used a DC power plug from another device that uses the same plug, but plug that goes into the wall outlet is a huge block and a pain to pack with all the other gear I got.


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## JohnWill (Oct 19, 2002)

Have you checked the power consumption of the 80gig drive? I have a 30gig and a 60gig drive in 2.5" cases, both run fine from my laptop. It will depend on the laptop, though they're "supposed" to universally supply 1/2 A at +5V for each USB connection.

You know you can find a lot smaller +5V P/S modules, perhaps that's something you should look into.


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## ~Candy~ (Jan 27, 2001)

JohnWill said:


> Candy, I use both of my 2.5" drives with no extra power on my laptop. Both of them have a dual-headed USB cable, the second USB connection is just to double the power available to the drive.


Interesting. I only have one USB port on my laptop  Guess it wouldn't work that way with a hub, huh?


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## JohnWill (Oct 19, 2002)

I think you need two for most hard disks, the .5A just isn't enough for them. My old 20gig one would fire up without a second connection, but none of the larger ones will.


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## Jerold (Jun 23, 2004)

JohnWill said:


> You know you can find a lot smaller +5V P/S modules, perhaps that's something you should look into.


Can you explain what you mean by the smaller +5V P/S Module?

Can you look over the drive specs for me to see about the power requirements? I thought that I read it right when I ordered the cables.I also have a DELL Precision M70 Laptop. I'll check on the specs for those USB ports. It comes with 2 pairs of USB2.0 on the laptop.

IBM Hitachi Travelstar 5K80 80GB ATA-6 2.5in 5400RPM Mobile Hard Drive

Power Requirement: +5VDC(±5%) 
Dissipation (typical):
Startup (max. peak): 5.0 W
Seek (average): 2.6 W
Read (average): 2.5 W
Write (average): 2.5 W
Performance idle (average): 2.0 W
Active idle (average): 1.3 W
Low power idle (average): 0.85 W
Standby (average): 0.25 W
Sleep: 0.1 W
Power consumption efficiency (watts/GB): 0.011


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## Jerold (Jun 23, 2004)

I just opened up the case and took a look at what the drives power requirements are as listed on the HDD. It reads this exactly:
5V 1.0A DC

Does this mean that theoretically, connecting 2 USB plugs into should fulfill the 1.0A power needs? I checked out the specs on the cable that i bought and it seems to provide 900mA. Does this mean that it is short of the full 1.0A?


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