Would a PWM Fan Splitter Cable work well for controlling 2 PWM fans off of one motherboard header?

[CloudHD]

Recently I found out that I can't control 1 of my 2 Noctua NF-F12 pwm fans rpm off one of my 3 pin motherboard headers. Knowing this, I figured why not just split the one 4 pin fan header I have right? However I was wondering would there be any risks to this? I saw other splitters that used molex connections for powering the fans. This worried me that I may mess up my mohterboard by trying to draw too much power out of one header. So knowing that, what risks would be posed by using a pwm fan splitter cable (without the molex connection) to power 2 pwm fans?

Thanks

 

[EAJuggalo]

Most likely is that it just wouldn't work. If the 4 pin is setup as the CPU fan it's possible to fry your processor if the fan isn't working. I tried this with 3 pin headers and could only get one of the fans hooked to the splitter to work at a time. I came to the conclusion I would either have to buy a fan controller or use the molex, I chose the molex.

 

[Paperdoc]

First of all, the answer may depend on how the fan is used. If, for example, both are used for your CPU cooling as EAJuggalo assumed, you certainly would not want to power one from the CPU_FAN port and the other from a CHA_FAN port. (Only the CPU_FAN port is controlled by the temperature measured inside the CPU chip.) But if they are both for the CPU, OR both used for case ventilation, you could use a 4-pin splitter. Most mobo fan ports can supply enough power for two fans, but not more.

If they are both used for case ventilation, you could use a splitter also. But you also should be able to use a mobo 3-pin CHA_FAN port if you want to. I am surprised you say you "found out that I can't control 1 of my 2 Noctua NF-F12 pwm fans rpm off one of my 3 pin motherboard headers". How did you find this out? In that situation, a 4-pin fan plugged into a 3-pin mobo SYS_FAN header should behave exactly as a 3-pin fan would and the port can control its speed. So, did you try this and find it did not work? Or, did you read somewhere that it can't be done?

Another thought: did you plug the second 4-pin fan into a mobo 3-pin port called PWR_FAN? If you did, that port exercises NO control over any fan connected to it, and the fan always runs full speed. Use a mobo CHA_FAN port.

 

[turbopixel]

I know there are fans where you can add another fan to it. It have that extension for. I don't remember what brand it was, maybe Scythe. That would be no help to you, I know. But maybe you end up buying one/two.

 

[Paperdoc]

I think what turbopixel is talking about is the type of fan designed to plug directly into a 4-pin Molex power output from the PSU. Many of those have a male 4-pin Molex connector on the end of their wires to get power, PLUS an additional 4-pin female Molex connector to "replace" the one that was "used up" when you plugged in your fan. These make sense because those power outputs can supply lots of current sufficient for many fans from one PSU output connector. That is quite unlike the limited power available from a mobo fan port. However, that type of fan cannot be plugged into a mobo 3- or 4-pin fan port for control by the mobo - the connector is wrong.

 

[CloudHD]

First of all, the answer may depend on how the fan is used. If, for example, both are used for your CPU cooling as EAJuggalo assumed, you certainly would not want to power one from the CPU_FAN port and the other from a CHA_FAN port. (Only the CPU_FAN port is controlled by the temperature measured inside the CPU chip.) But if they are both for the CPU, OR both used for case ventilation, you could use a 4-pin splitter. Most mobo fan ports can supply enough power for two fans, but not more.

If they are both used for case ventilation, you could use a splitter also. But you also should be able to use a mobo 3-pin CHA_FAN port if you want to. I am surprised you say you "found out that I can't control 1 of my 2 Noctua NF-F12 pwm fans rpm off one of my 3 pin motherboard headers". How did you find this out? In that situation, a 4-pin fan plugged into a 3-pin mobo SYS_FAN header should behave exactly as a 3-pin fan would and the port can control its speed. So, did you try this and find it did not work? Or, did you read somewhere that it can't be done?

Another thought: did you plug the second 4-pin fan into a mobo 3-pin port called PWR_FAN? If you did, that port exercises NO control over any fan connected to it, and the fan always runs full speed. Use a mobo CHA_FAN port.

Sorry for the super late reply. I ended up figuring out a solution that I think works but maybe you guys can confirm. I currently use my CHA_FAN1 PWM Connector splitted to both fans. I originally found out that the setup I had was not working (1 to a 4pin connector and the other to a 3 pin) when I put the computer on silent mode in the uefi. I noticed one of the fans wasn't spinning up. After I did some research I found out it was probably due to the fact that the 3pin headers use voltage to control speeds as compared to the PWM header. What I realized after looking at noctuas website is that the voltage being delivered was not enough to start the fan and keep it going.

After doing a bit more research on here I found out it should be safe and I shouldn't fry anything using a splitter for 2 fans as long as the amperage (I think that was it) was not too high. I found out the max one header on my motherboard could handle and I was in the clear. My current solution with the splitter to 2 fans works perfectly. I can control the speeds in the uefi and had not had any problems within this month. Let me know what you think of my solution.

 

[Paperdoc]

If I read this correctly, the two fans you are talking about both are used for case ventilation, and both are of the 4-pin type. You now have a 4-pin fan splitter connected to the mobo's CHA_FAN1 port (which is 4-pin) and feeding those two fans, and it is all working just fine.

Yes, that is a good way to do this.The only restriction on this is, as you say, total amperage of the two fans. Most mobo fan ports can supply up to 1 amp max. Many case ventilation fans consume 0.1 to 0.2 amps when running, BUT for a few seconds at start-up they consume 2 to 3 times that. So to connect TWO fans like that to one port is OK, but not more.

The real caution, however, is for those who have chosen high-power fans for super fair flow, because such fans can consume 0.3 to 0.6 amps EACH (or more in a few cases) at running time, and a LOT more for start-up. You cannot use a splitter to connect two of those high-power fans to one port.

 

[CloudHD]

If I read this correctly, the two fans you are talking about both are used for case ventilation, and both are of the 4-pin type. You now have a 4-pin fan splitter connected to the mobo's CHA_FAN1 port (which is 4-pin) and feeding those two fans, and it is all working just fine.

Yes, that is a good way to do this.The only restriction on this is, as you say, total amperage of the two fans. Most mobo fan ports can supply up to 1 amp max. Many case ventilation fans consume 0.1 to 0.2 amps when running, BUT for a few seconds at start-up they consume 2 to 3 times that. So to connect TWO fans like that to one port is OK, but not more.

The real caution, however, is for those who have chosen high-power fans for super fair flow, because such fans can consume 0.3 to 0.6 amps EACH (or more in a few cases) at running time, and a LOT more for start-up. You cannot use a splitter to connect two of those high-power fans to one port.

This is correct. It's just 2 fans so it shouldn't get above 1 amp. I looked on noctuas site and was able to figure out both together used 0.2. Hopefully all will fare well in the future. Now to move on to fixing this RAID issue I am having. Thanks for the reply!

 

[Finkledbody]

Recently I found out that I can't control 1 of my 2 Noctua NF-F12 pwm fans rpm off one of my 3 pin motherboard headers. Knowing this, I figured why not just split the one 4 pin fan header I have right? However I was wondering would there be any risks to this? I saw other splitters that used molex connections for powering the fans. This worried me that I may mess up my mohterboard by trying to draw too much power out of one header. So knowing that, what risks would be posed by using a pwm fan splitter cable (without the molex connection) to power 2 pwm fans?

Thanks

Just check to see how many watts/amps each fan pulls and do the math. Most mobo CPU headers are roughly 10-13 watts or 1-2 amps.
Personally, I have two Noctua iPPC-3000 PWM fans hooked up to one CPU-fan 4 pin header through a y splitter. Each fan pulls .9amps or 1.8 amps total. I keep them maxed out at all times. Both fans working correctly.