Is it safe to plug multiple case fans to a single 4 pin header using a fanhub?

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IzzanScool

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So i have a motherboard (Asrock FM2A68M-HD+) that only has one four pin chassis fan header, and I'm thinking of connecting about 3 or 4 120mm fans using a deepcool fan hub into this single header, is this safe? This is my first build
 
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raisonjohn
You need to check the amp draw of each fan you will plug in. Check the back of the fan (sticker label), or the box, or the specs for that. You want your total amp draw for all the fans connected to a single header be less than 0.75A for safety (headers are usually up to 1A max, but some selected headers have higher amp capacity).

So, for example, if your fans are 0.25A each, you can safely plug 3 (not 4). If the fans are rated 0.30A, I'd only go with 2 (not 3). If the fans have different amp draw, say, 0.12A, 0.2A, 0.18, and 0.23A, then you can safely run them all.
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raisonjohn

raisonjohn

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You need to check the amp draw of each fan you will plug in. Check the back of the fan (sticker label), or the box, or the specs for that. You want your total amp draw for all the fans connected to a single header be less than 0.75A for safety (headers are usually up to 1A max, but some selected headers have higher amp capacity).

So, for example, if your fans are 0.25A each, you can safely plug 3 (not 4). If the fans are rated 0.30A, I'd only go with 2 (not 3). If the fans have different amp draw, say, 0.12A, 0.2A, 0.18, and 0.23A, then you can safely run them all.
 
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Paperdoc

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raisonjohn is right. The root of this problem is that the Deepcool item you mention is NOT a HUB, in my opinion. To me, a Hub gets power for all its fans from a PSU output and thus avoids the 1 amp limit of a mobo CHA_FAN header. This Deepcool unit does not do that. To me, it is a 4-port 4-pin SPLITTER that simply connects all its fans to the power available from its mobo header, and thus the warnings raisonjohn has given.

If you want to be safer or if you need more than 1 amp capacity for your fans in total, get a real 4-pin fan Hub, such as this

https://www.newegg.com/Product/Product.aspx?Item=N82E16882422018&cm_re=fan_hub-_-82-422-018-_-Product

That's a simple exposed circuit board. It comes with a cable with three connectors. One large one connects to a 4-pin Molex (aka Peripheral Power) output from the PSU for fan power, one smaller one with 4 wires to it connects to a labelled connector on the END of the board, and one smaller one with two wires plugs into your mobo's CHA_FAN header. This last connector picks up the PWM signal that the Hub needs from the CHA_FAN header and returns to it the speed signal from ONE of the fans plugged into the Hub - specifically, only from the fan plugged into the board's output labelled "RPM". The Hub gets power for all its fans from the PSU, and sends the PWM control signal from the CHA_FAN mob header to all those fans for controlling their speeds.

Here is another model, one that is enclosed in a box.

https://www.newegg.com/Product/Product.aspx?Item=N82E16811999309&cm_re=fan_hub-_-11-999-309-_-Product

It has slightly different connectors that accomplish the same thing. Its power input comes from a SATA power output from the PSU, rather than from a Molex output. And its only port that reports fan speed back to the mobo CHA_FAN header is the one identified by case grooves on one corner.

A hint on that mobo. Its manual says that, BOTH for the CPU_FAN header and the CHA_FAN header, it is set by default to run those fans at full speed always. You should change tha to "Automatic Mode" for each fan header so that the fan speeds can be adjusted by the mobo according to actual cooling needs.
 
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