External Hard Drive Power Adapters

**fatejd** · 10-10-2006, 12:47 PM

I think this is the right place to ask this:

I have an external drive that I want to add to my computer and am probably going to end up connecting the power directly to the PSU via a molex connector. I know not all external drives have the same rated "power bricks" or power adapters, but if I connect one to the PSU in this way, wouldn't it just grab as much power as it needs no matter what the power adapter gives it? I just don't want the power from it to do anything to the HD like fry it or anything. A fuse would probably protect it right?

Thanks

**DarquePervert** · 10-10-2006, 02:22 PM

Originally Posted by fatejd

I think this is the right place to ask this:

Not really, but I moved it.
Hardware Development subforum is for people designing new hardware. Sound logic, though.

I have an external drive that I want to add to my computer and am probably going to end up connecting the power directly to the PSU via a molex connector. I know not all external drives have the same rated "power bricks" or power adapters, but if I connect one to the PSU in this way, wouldn't it just grab as much power as it needs no matter what the power adapter gives it? I just don't want the power from it to do anything to the HD like fry it or anything. A fuse would probably protect it right?

Thanks

No. That's not correct. Let's say the external hard drive requires 5v and you provide it 12v. You're providing 2.2 X the rated power, which it won't be able to handle. You'll destroy the device if you provide too much power.
Too little power will likely result in the device not working and probably won't damage it.

**fatejd** · 10-10-2006, 03:33 PM

Originally Posted by DarquePervert

Not really, but I moved it.
Hardware Development subforum is for people designing new hardware. Sound logic, though.

No. That's not correct. Let's say the external hard drive requires 5v and you provide it 12v. You're providing 2.2 X the rated power, which it won't be able to handle. You'll destroy the device if you provide too much power.
Too little power will likely result in the device not working and probably won't damage it.

So, I should probably use the supplied brick and "alter" the plug (i.e. cut off the wall plug and get the power and ground wires) to attach to the molex, right?

DIGItonium · 10-10-2006, 04:10 PM

Bypass the power circuitry that powers the drive (i.e., disconnect the power connector of the hard drive). Then connect the 4-pin Molex to the drive with the PSU.

Here's the catch - I'm assuming this is a USB external hard drive. You'll need to power the USB=>IDE adapter since I doubt it is getting power from the USB connector, itself.

What you could've done is get a blank external hard drive case, and then grab a USB-to-IDE or SATA-to-IDE adapter. Then Have the larger 4-pin Molex power the drive, while the smaller 4-pin Molex power the USB or SATA adapter. Ah, look here! The adapter below does it all!

http://www.addonics.com/products/io/adideu2.asp

**fatejd** · 10-10-2006, 05:05 PM

I might look into that, thanks for the info. If I ever give up on the external HD idea, this would be an easy conversion of an internal IDE HD.

**Vineet Singh** · 10-11-2006, 01:12 AM

Another, only $15

http://www.tigerdirect.com/applicati...1205&CatId=470

Looks like it uses a standard molex just for the drive.

**ajamils** · 10-11-2006, 04:11 PM

Originally Posted by Vineet Singh

Another, only $15

http://www.tigerdirect.com/applicati...1205&CatId=470

Looks like it uses a standard molex just for the drive.

you'll still need external power brick to make it work (look at the pics)

**fatejd** · 10-11-2006, 04:47 PM

I got a SATA > USB converter and SATA power > molex converter from newegg - now I'll be set once I get my HD replaced from Seagate

DIGItonium · 10-12-2006, 04:32 PM

^ Good luck! It's so simple, but I always cross my fingers the hardware gets detected properly. I'm using a SATA CF adapter on an Intel board. XP just refuses to detect the storage medium.

**fatejd** · 10-12-2006, 04:36 PM

That stuff will be here on Monday, but I have to send my drive into Seagate to get replaced, so it will be a little while before I can test this out for sure, unless I just jack a HD out of my computer for testing.