External Enclosure Fan Mods

signal64 · Post by **signal64** » Tue Apr 18, 2006 8:56 pm

Hey all,

I've been thinking about some options for keeping the fan noise down in External Drive enclosures.

It seems that the majority of enclosures make no attempt to keep those little fans quiet (especially when they are not in use).

In my scenario, I have a Plextor 740UF (30x30x10mm 5v fan) and a Lian Li EX-125 (40x40x10mm 5v fan). Both of these fans are fairly noticeable from a distance if none of my other systems are on.

So, I had a few ideas I wanted to run across the forum.

1. Replace the fans with a quiet one.

Ok this is pretty obvious. However information on a good 5v fan replacement has been a bit of a challenge to find.

2. Voltage Control

Both fans being 5v seems to eliminate this option?
I need to do some tests to see how much lower they can go, but not expecting by much.

3. Have the fan turn off if the system has been shutdown or has been disconnected from the enclosure.

As long as the USB / Firewire doesn't supply power when the system is off, I was thinking of a simple circuit to turn the the fan (or power to the enclosure board itself) off when not in use.

4. Thermal control.

Thought this one might be a bit more difficult as I haven't seen a small fan with temp control. An external circuit might work, but need to find out what the minimum voltage these can run at first.

Any comments or further ideas on this much appreciated.

Thanks

disphenoidal · Post by **disphenoidal** » Sun Apr 23, 2006 9:55 pm

How many drives are in each enclosure? I have a couple single drive enclosures that don't have any fans and seem to run fine. I don't have temperature monitoring on them, but they're only warm to the touch.

IsaacKuo · Post by **IsaacKuo** » Mon Apr 24, 2006 2:24 am

disphenoidal wrote:How many drives are in each enclosure? I have a couple single drive enclosures that don't have any fans and seem to run fine. I don't have temperature monitoring on them, but they're only warm to the touch.

The outside temperature of an enclosure doesn't tell you what the temperature of the hard drive inside is at. It just tells you roughly how much power the hard drive is consuming. Depending on how insulated the enclosure is, the internal temperature could be very much higher than the external temperature.

signal64 wrote:However information on a good 5v fan replacement has been a bit of a challenge to find.

Most 12v fans will run at 5v; they'll just be quieter and have less airflow. That's not a problem.

The real problem is fan size. You really want an 80mm fan in order to get a decent amount of airflow when silent. A hard drive doesn't really require much airflow, though, so you could get away with a 60mm fan. But 40mm? In my experience, there's just no way to get a useful amount of airflow from a 40mm fan running silent.

disphenoidal · Post by **disphenoidal** » Mon Apr 24, 2006 9:09 am

IsaacKuo wrote:
The outside temperature of an enclosure doesn't tell you what the temperature of the hard drive inside is at. It just tells you roughly how much power the hard drive is consuming. Depending on how insulated the enclosure is, the internal temperature could be very much higher than the external temperature.

That is very true, but one day I opened up the enclosure after running the drive to see how hot it actually got and whether it was quieter without the enclosure. The drive was warmer than the outside of the enclosure, but stillnothing to be concerned with.

signal64 · Post by **signal64** » Mon May 01, 2006 6:49 pm

For the issue with constantly being powered on, I found a nifty little solution.

http://www.cpustuff.com/estore/product. ... =0&page=1

It simply looks for +5v on the USB line and throws an AC relay.
You have to make sure your motherboard doesn't keep +5v on the USB line when the system is powered off, but the majority of motherboards come set that way by default.

I have one installed and it's working out great.

As far as the noise goes, it's still an issue. I can still hear them when the system is on (now that I got the system running very queit).

The 30mm fan is 5v so it's been difficult to find quiet replacements.

I stand corrected, the Lian Li is using a 12v fan.

I tried more than a few 40mm 12v fans and couldn't find anything quiet or would work reliable at 5v.

Both these enclosures have DVD burners in them, so full time cooling is not required.

I know these burners generate some heat on longer burns (i.e. Full DVD or DVD DL) so didn't want to eliminate the fan altogether.

A couple of generic CD burners don't use fans at all, so torn between going that far with a DVD burner.

Still on the hunt for some suggestions for a 40mm and 30mm +5v replacement solutions or a small enough circuit to control the fan.

A modded Zalman fanmate maybe?

signal64 · Post by **signal64** » Mon May 01, 2006 10:52 pm

Funny enough I made one last dig through my junk fan box and found a Radio Shack 40mm 12v fan (cat no. 273-240). I think I got this over a year ago for a different project.

At 12v this thing is pretty darn noisy (which is why I probably didn't use it) and emitts the higher pitch whine that I'm trying to get rid of.

I tried it out at 5v and it works like a champ. MUCH quieter than I would have thought. Was able to drive it down to 3.9v reliably.

In open air at 5v I can't hear anything until I get it within maybe 3-4cm of my ear. At 3.9v I can't hear anything except air flow (which is still very quiet), but the fan does vibrate a bit.

Airflow seems to be decent enough for this application (i.e. DVD Burner).

I can't find one spec on this thing so I can't tell you what it's supposed to be rated at.

Note: Unfortunatly Radio Shack just rebrands things from different manufactures and sells them under the same part number. Looking at their site, this fan is no exception. It looks different than the one I have so maybe I just got lucky.

It might be worth a try though for someone else.

Still looking for a solution to that 30mm +5v though.