Two fans on one connector?

[mojothehut]

Hey all,
I'm out of 4 pin fan connectors on my motherboard (Asus Maximus VI Hero)
It only has three 4pin fan connectors and I want to hook up a 4th 140mm fan.
There is a "cpu optional" connection I could still use but for whatever reason I can't monitor that slot with software from windows, can only see it in bios.

Can I use a split like this http://www.newegg.com/Product/Product.aspx?Item=N82E16812718001
to run two 140mm fans off one motherboard connection? I'm not sure of the needed power requirements. All my fans are corsair 140mm 1k rpm fans.

 

[Ketchup]

Should be fine. High RPM for such a large fan could get you in trouble, but at the speeds you are talking, I don't see a problem.

 

[mojothehut]

Cool
Here is the fan that I'll be using 4 of, with 2 on one of those spliters.
Technically 1200rpm
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181049

 

[BonzaiDuck]

Cool
Here is the fan that I'll be using 4 of, with 2 on one of those spliters.
Technically 1200rpm
http://www.newegg.com/Product/Product.aspx?Item=N82E16835181049

If you want my opinion, you should invest in a PWM splitter that allows the mobo CPU_FAN or CHA_FAN PWM signal to control the fans while powering the fans directly from the PSU. This means you could have as many as 7 or 8 fans controlled from that PWM signal, without any power-draw from your motherboard. Look at the Swiftech 8W-PWM-SPL-ST unit. You can probably get it at either FrozenCPU or SidewinderComputers.

 

[mojothehut]

That PWM splitter looks awesome! Think Ill try that!
So I have a modular PSU (corsair 750) and right now just had one sata power cable running my single SSD and DVD player. Should I hook this up to that one cable or attach another one to the psu for it?

 

[ratjacket]

you can just wire them up to the psu direct aswell for always on always full speed, into a molex plug etc

 

[BonzaiDuck]

you can just wire them up to the psu direct aswell for always on always full speed, into a molex plug etc

Yeah, but the point of the Swiftech and similar splitter-devices: they allow you to monitor one PWM fan or pump, with another seven fans/pumps of any amperage and speed varied according to a curve with CPU temperature -- on a "duty-cycle" or percentage basis.

In my rig, for instance, I've dispensed with two Noctua 120 and 140 on my D14 cooler, replaced them with a single Akasa Viper 140. I also got rid of a bottom-panel 140mm fan because it adds nothing to airflow compared to the two 200mm fans in my [HAF -- that explains it] case.

I have two possible configurations to choose from for my 3-pin exhaust fan, which I am replacing with a PWM fan. For the first, I rigged up a 120-to-140mm adapter for a square Akasa Viper 140.

The other configuration which I plan to test soon is an[Nidec-Servo] Gentle Typhoon that spins up to a maximum 4,250rpm and a rated 46 dBA of noise. So that gives me two problems: eliminating the noise, and ducting the exhaust to the exhaust-side of the D14 cooler.

IF I eliminate a good portion of noise that was already scientifically tamed and tuned by the manufacturer of the GT fan, I can probably run it up to top end for high CPU temperatures. If it's paired on a Swiftech 8W-PWM-SPL splitter with the Akasa Viper, the Viper has to vary between maybe 500 RPM to 1,600 RPM. The GT fan -- probably from 1,000 RPM up to the top-end. So I need to set the fan curves so that both fans at low and high percentage duty-cycle will work as intended in the speed ranges chosen for both. And I can only monitor the speed of one fan or another, unless I run one of the tach wires to a spare motherboard fan port.

 

[Meghan54]

I'm not sure of the needed power requirements. All my fans are corsair 140mm 1k rpm fans.

That fan draws .23A (2.76W) running at its full speed. Should be able to see that on the fan's hub label, but also found in the chart here:

http://www.corsair.com/en-us/air-se...uiet-edition-high-airflow-120mm-fan-twin-pack

Your motherboard's manual only lists one fan header's output, the cpu_fan output, and that's 1A (12W), but I doubt the other headers are any different. Two of your fans would draw .46A (5.52W) so no big concern at all. Just remember, fans do typically draw a bit more on startup, but even with that, you're probably well under the header's output limit. I doubt the fans are going to double their amperage draw on startup.

 

[mojothehut]

Wow, thanks for looking that up for me =)