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Can I wire two fans into one MB fan power socket?

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April 10, 2007 6:32:47 PM

I have an ASUS P5W DH Deluxe motherboard of which I'm using 4 out of the 5 fan sockets. However, I want to use the unused 'Power 2' socket to power my redundant Intel fan and Asus heatsink fan to add extra cooling to the Northbridge/Memory and Southbridge components.
Basically, without any adverse effects, can I splice the two into one plug and power each off the one socket?
April 10, 2007 7:12:27 PM

Quote:
I have an ASUS P5W DH Deluxe motherboard of which I'm using 4 out of the 5 fan sockets. However, I want to use the unused 'Power 2' socket to power my redundant Intel fan and Asus heatsink fan to add extra cooling to the Northbridge/Memory and Southbridge components.
Basically, without any adverse effects, can I splice the two into one plug and power each off the one socket?


I've done it with low-current draw fans. Go shop around for fans and compare the current spec. I would not run two 12cm high RPM fans off of one header unless I first checked with tech support for your mobo maker.
April 10, 2007 7:24:37 PM

Yes you most likely will be fine. I have two 80mm case fans spliced together running of my motherboard's fan2. This way I can use speedfan to control them. I've been doing this for about 4 months and everything works fine. But as Clue69Less said, probably safe to stick with lower power fans.
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April 11, 2007 3:07:38 AM

Wouldn't it just be simpler to use an adapter and a molex connector? Or am I missing something?
April 11, 2007 3:31:34 AM

As others have said, yes it can be done.

The thing to watch is the current draw.

Usually, a motherboard fan lead will be limited to between 1 amp and 1.6 amps.

Most 80mm fans I have seen are specfied to run on a small fraction of that.

What the specs don't tell you is there is a large current draw spike when any motor is first turned on and that this spike increases with age.

So, while two low draw fans may work fine for several years, eventually it will probably be damaging in some way.

The short of it is, while possible, it is not advisable.
April 11, 2007 3:56:51 AM

That's an good question and one that I'm interested in as well. I purchased y connectors to connect 2 fans to 1 fan header. The fans I'm using are rated at .15a so I thought the two running at .3a would be fine. I failed to consider the surge when powering up and was wondering if that might still be safe (don't want to fry my Stryker)
April 11, 2007 4:01:40 AM

it will work fine, lol, generally fans of average stature have no problems, for fecks sake, i had an acer rig that used to be my main but is now being used for bittorrent had a copper heatpipe designed heatsink and a 2.6amp,12v dc blower on it, sounded like a vacuum at 6k rpm btu keeps the c2d e4300 at a nice cool 40oC under load.
April 11, 2007 4:37:49 AM

I've been running two 80mm fans off of one socket for over a year and haven't had any problem with it on my ASUS board. Like others have said, check the combined power draw of the fans and make sure its less then what the socket supplies.
April 11, 2007 4:53:12 AM

I had a minor "problem" on an intel board in that the feedback signal (the white wire) coming from the two fans combined was confusing the motherboard. It couldn't figure out how fast the fans were going. Cutting the wire going to one of the two fans solved that problem. One runs as the speed feedback master, and the other as a slave.
April 11, 2007 5:04:16 AM

i can already smell burnt fan headers...
April 11, 2007 5:32:08 AM

Quote:
i can already smell burnt fan headers...
Now thats just being negative...I bet it'll work just fine. Like my friend's pc yesterday. I built him a C2d with 2GB of ram, 2 DVDRWs, a 7600GS and 2 120GB drives on a shitty 300w PSU with 9A 8O on the 12V rail. I hope he doesn't stress it too much...well, he didn't want to buy a better psu so it'll be his loss...
April 11, 2007 5:35:42 AM

Quote:
i can already smell burnt fan headers...
Now thats just being negative...I bet it'll work just fine. Like my friend's pc yesterday. I built him a C2d with 2GB of ram, 2 DVDRWs, a 7600GS and 2 120GB drives on a shitty 300w PSU with 9A 8O on the 12V rail. I hope he doesn't stress it too much...well, he didn't want to buy a better psu so it'll be his loss...

i already smell burnt hardware...
LOL
April 11, 2007 5:39:49 AM

Quote:
i already smell burnt hardware...
LOL
I hope not. He's been complaining the last 2 months coz his socket A mobo went and he was too lazy to look for another...I'm gonna kick his azz if he starts complaining again.
April 11, 2007 8:18:44 PM

Quote:
i can already smell burnt fan headers...


Talk to me. You serious? I am using low-current fans that don't add up to near the rating of the header, so I figured it would be ok. Is this just a really bad idea?
April 12, 2007 12:34:39 AM

Quote:
i can already smell burnt fan headers...


Talk to me. You serious? I am using low-current fans that don't add up to near the rating of the header, so I figured it would be ok. Is this just a really bad idea?

Of course i was kidding. BUT i have seen so many cases of people burning the fan headers, even with one large current drawing fan, that i wouldn't be surprised if at some point the header died mysteriously!
If you start up and shutdown the machine frequently, it will die much sooner, due to large current draw to start the spin. Once its spinning its easier on the header.
April 12, 2007 3:24:14 PM

Quote:
i can already smell burnt fan headers...


Talk to me. You serious? I am using low-current fans that don't add up to near the rating of the header, so I figured it would be ok. Is this just a really bad idea?

No, its not a bad idea. Sometimes its an unnessary idea, like if your board has 2 or 3 fan headers and you're hooking the multiple fans into one header. Other than that, if the fans have a lower current draw than what the header provides, worry about other things.
!