Power consumption of 2.5" IDE drives,

[Goi]

Hi,

Does anyone know which 2.5" IDE(not SATA) drives consume the most power? I've seen datasheets that claim about 2-3W during seek and about 4-5W during spinup. I'm more concerned with the spinup current spike since I'll be using it with bus powered USB enclosures. I'd imagine the more platters/head it has and the faster the rotational speed, the more and the longer the spinup current would be?

 

[corkyg]

They are rated at 5 vdc at .4 to .6 A. I have an external 160 GB, 5400 RPM Seagate, and the external power module can provide 5 vdc at up to 2.6 A. So your datasheet numbers are ceretainly within the realm of reality.

This is why even 2.5" externals (USB or Firewire) frequently require an external power "brickette" in order to maintain the connection, especially on laptops.

Laptop externals often have two cables - the USB data cable and a second USB to a power pin so more power can be applied when needed.

 

[Goi]

Yup, I know about the USB Y cable. That allows the drives to draw up to 1A theoretically, assuming the USB ports are full powered 500mA ones and are well behaved. The 0.4-0.6A is actually an operating average max though. It doesn't take into account the spinup current required, which is usually something to the order of 0.9-1.1A. That is why I'm concerned. So, which are the most power hungry 2.5" IDE(non-SATA) drives out there?

 

[tcsenter]

Like we are going to download the datasheets for every make, family, series, and model of 2.5" drive? The answer is out there, get cracking.

I have used a few 2.5" drives with +5V DC load rating of .5A ~ .7A that work fine in bus-powered USB2.0 enclosures with no trouble at all. The 500mA max current per USB port is a continuous rating. A USB port should be able to handle higher transient or peak loads (e.g. during spin-up).

 

[corkyg]

That is all true. But there are other factors that may not be common to all systems. I happen to presently have 6 external drive cases for 2.5's. They are combo cases, USB 2 or Firewire.

I can use them w/o supplemental power with Firewire on my desktops. My laptop's USB ports are all filled, and one goes to a powered hub. Even that will not spin up or "see" any of the external cases. So, I use a 5 vdc supplemental power module, and they all work that way.

With that arrangement, it really doesn't matter what each draws (they are Toshiba, Hitachi, Fujitsu and Seagate, some 4200 and some 5400.) The drive RPM will also impact on the transient peak load for spin up. A 4200 draws less than a 5400 and than a 7200.

My choice is to use supplemental power and not worry about the transients.

 

[Goi]

Thanks. I've actually done my homework by downloading just about all relevant datasheets from manufacturers who release such information. I was just wondering if in the real world things are different, or are there higher powered drives out there whose datasheets don't reveal such information. I've also looked at 2.5" roundups on tech-report and storagereviews that actually measure power as well.

AFAIK, rotational speed only increases the amount of energy required to spinup the drive to its final rotational speed, but not necessarily the power. It can take the same power but just take longer to spin up to the speed. I guess it's the same for number of platters as well, except manufacturers would be forced to up the power consumption if they wish to keep spinups to a certain duration...

Anyway, AC adapters are fine and dandy, but if I'm on the move with a laptop, it'd be kinda hard to find an AC socket, and if I do happen to find one, I'd be using it for my laptop rather than the drive. It's also be a pain carrying so many AC adapters around. Also, after inspecting several USB enclosures out there, it seems that most enclosures simply short VBUS and the 5VDC from the jack. That sounds like a bad idea to me since you're essentially shorting 2 power supplies. These are some reasons why I'd like to stick with bus powered if possible.

 

[corkyg]

OK - I understand your concerns. I am on the road frequently - domestically and abroad, and have never not had access to A/C outlets. But - you are right about carrying stuff in that mode. That is why, when I travel, the external drives stay home. My main laptop drive is now 160 GB - and there is plenty of room for anything needed for the trip. If you really need low power external storage capacity, then consider this:

Micro