Sign in with
Sign up | Sign in
Your question
Solved

Fan Y Cable Splitter

Last response: in Systems
Share
August 24, 2009 4:46:30 PM

I have a CPU heatsink installed with 2 fans in a push pull configuration. Do you guys thinks it is OK to use a fan splitter and connect both fans to the 3 pin cpu fan header on the motherboard? I afraid of too much voltage on one header. Here is a link to what I am talking about.
http://www.newegg.com/Product/ProductList.aspx?Submit=E...

More about : fan cable splitter

a b B Homebuilt system
a c 190 à CPUs
August 24, 2009 5:03:20 PM

It should be fine, the voltage will be the same, nature of a parallel circuit, however the current will be doubled but fans dont pull very much anyway so it shouldnt be an issue.
m
0
l
a b B Homebuilt system
August 24, 2009 5:03:48 PM

It will increase your current draw for sure, don't think it will affect voltage. Your motherboard doesn't have more than one 3 pin fan header on it? It would be safer to just take the one designated for case fan and hook your second one up to that. If you have a case fan already plugged in there, just convert the 3 pin to a molex type connector and string it on to your PSU.
m
0
l
Related resources
a b B Homebuilt system
a b à CPUs
August 24, 2009 6:17:10 PM

What you propose is OK with two cautions:

1. As others have said, both fans will get the same voltage but the mobo will have to supply twice as much current. Don't know whether that is OK - maybe mobo maker can advise the current limit on the CPU fan header. Compare that to specs from the fan supplier.

2. You MUST solve another problem. Each fan has 3 pins - ground (black), Supply Voltage (red) and fan speed OUTPUT (Yellow). The speed signal goes from fan to mobo so the mobo can check that it's working and send alarms if needed. You cannot send two such signals to the mobo from 2 fans on one pin. In re-wiring the fans, connect only ONE of the yellow leads from the fan to the mobo connector; leave the other fan's speed line disconnected.
m
0
l
August 24, 2009 7:17:20 PM

I was under the impression the yellow wire was just to output the current RPM of the fan. I believe the speed is controlled with the output of the voltage going to the fan. Any case I would not recommend this configuration. If you are really concerned with it then buy a fan controller. If not, then I would use a molex converter on one fan and connect the other to the mobo.
m
0
l
August 24, 2009 7:18:47 PM

Sorry Paperdoc, I read the post and replied to fast. You are right on the money with what I was thinking.
m
0
l
August 24, 2009 8:35:28 PM

Thanks for all your responces guys. I think I will just leave it the way it is (one fan with a regular motherboard fan header and the other in the cpu fan header).
m
0
l
August 24, 2009 8:50:24 PM

ragsters said:
I have a CPU heatsink installed with 2 fans in a push pull configuration. Do you guys thinks it is OK to use a fan splitter and connect both fans to the 3 pin cpu fan header on the motherboard? I afraid of too much voltage on one header. Here is a link to what I am talking about.
http://www.newegg.com/Product/ProductList.aspx?Submit=E...

I have my Thermalright Ultra120 eXtreme-1366 RT CPU Cooler set-up in the Push/Pull configuration using a Y-splitter cable connected to the CPU Fan mobo connection and it works fine with no problems at all for the part 7 months.

Below is two Y-splitter cables for you to check out, one is longer then the other.
3-Pin Y-Adapter Cable 12" Sleeved $4.95
http://www.performance-pcs.com/catalog/index.php?main_p...

3-Pin Y-Adapter Cable 4" Sleeved $3.95
http://www.performance-pcs.com/catalog/index.php?main_p...
m
0
l

Best solution

a b B Homebuilt system
a b à CPUs
August 25, 2009 2:59:28 PM

Connecting one fan to a "regular mobo fan header" means that fan on the CPU is not being controlled by the right signal. Some mobo's control the fan speed (by voltage) on BOTH of their SYS_FAN headers according to the measured temperature of the mobo itself, and not according to CPU temp. Now, quite possible that there's a good relationship between CPU temp and mobo temp and this system is better than no control at all, but it is not really the same as doing what you proposed originally. Other mobo's control only the SYS_FAN1 pinout by mobo temp, and the SYS_FAN2 is not controlled at all - just provides full fan speed. Its advantage over a simple connection to a Molex connector is that the mobo connection allows the mobo to monitor the speed of the second CPU fan (always full speed) and send out an alarm if it fails.

In my previous post, item 2 mentioned avoiding clashing speed signals from two fans in parallel. Easy to do that. On the Newegg page you linked to, the second item by Link Depot makes one mobo 3-pin CPU_FAN pinout into 2. Just cut one of the two yellow wires (and tape off the ends) so only one fan speed signal is being sent to the mobo.
Share
November 18, 2011 12:38:32 AM

i have the same problem as ragsters. As to what Paperdoc said, my question is... after cutting one of the fan's yellow speed wire, doesn't that mean the fan with the wire cut will not be able to get RPM readings?
m
0
l
!