Using multiple fans via one plug

[le_Acu]

Okay, so first of all, I'm new to all this tech stuff, so sorry if this is a dumb question

I'm using following parts; B150M night elf - motherboard & EVGA's 500B Bronze power supply

My motherboard has only one 3-pin fan connector plug, but I have x1 stock & x4 extra fans and I'd like to be able to use them all at once. 

 

This leads to my question; Can I just get Phobya's 6x 3-pin molex and plug in all the fans using one spot on mobo or is there a chance that it might burn my plug?

 

(not sure if this information is needed but my ''extra fans'' are Arctic F12s - https://www.arctic.ac/eu_en/f12.html & cable link - https://www.jimms.fi/fi/Product/Show/73340/at81043/phobya-y-haaroitin-3pin-molex-muunnos-6x-3pin-molex-60cm-musta)

 

Thanks.

 

[pwn_intended]

The molex connector will plug the fans directly into the PSU and not your mobo. There is no danger of burning anything out this way, but the fans will run at 100% the entire time then.

[le_Acu]

Ah okay, thanks!

[mariushm]

You should NOT plug more than 2-3 fans in one motherboard fan connector. To a power supply molex connector, you can go nuts, those can handle lots of fans.

 

Most fan connectors are rated for at least 1A but not much more. Fans usually consume about 0.15-0.25A but right when they start for the first time, for a second or so they use much more current, maybe even more than 0.5A (they have to overcome forces like friction inside the hub and inertia and start spinning the fan, once it spins the current drops).

So if you connect two or three fans, right when you start the pc, the 2-3 fans together will probably load the connector with more than 1A of current for a brief moment, and if the motherboard is properly designed, it will tolerate such momentary burst and then will be able to power those 2-3 fans continuously. If it's a cheaper motherboard, one random time, the connector may become damaged and stop working.

 

The molex connectors are rated for about 8A of current in complete safety. If you ignore the safety recommendations and don't care if wires between the power supply and the molex connector (or the metal contacts in the connector themselves) overheat, they can do even 10-12A.  So basically there's a huge amount of fans that could be connected and not go over that 6-8A value even at the boot time when each individual fan will pull more correct for a brief time.

[MValuableP]

10 minutes ago, mariushm said:

You should NOT plug more than 2-3 fans in one motherboard fan connector. To a power supply molex connector, you can go nuts, those can handle lots of fans.

 

Most fan connectors are rated for at least 1A but not much more. Fans usually consume about 0.15-0.25A but right when they start for the first time, for a second or so they use much more current, maybe even more than 0.5A (they have to overcome forces like friction inside the hub and inertia and start spinning the fan, once it spins the current drops).

So if you connect two or three fans, right when you start the pc, the 2-3 fans together will probably load the connector with more than 1A of current for a brief moment, and if the motherboard is properly designed, it will tolerate such momentary burst and then will be able to power those 2-3 fans continuously. If it's a cheaper motherboard, one random time, the connector may become damaged and stop working.

 

The molex connectors are rated for about 8A of current in complete safety. If you ignore the safety recommendations and don't care if wires between the power supply and the molex connector (or the metal contacts in the connector themselves) overheat, they can do even 10-12A.  So basically there's a huge amount of fans that could be connected and not go over that 6-8A value even at the boot time when each individual fan will pull more correct for a brief time.

Hey man,

 

I'm jumping on this thread as I also want to know something about this.

 

I have 4 fans (5 including cpu cooler) that I want to connect to my motherboard. Would I be best off connecting them all through a 4x4 pin molex, or just having one splitter, and the rest can be plugged into my mobo normally? And is there a downside to the fans running at 100% at all times?

[mariushm]

If you connect the fans to molex connectors, you're no longer able to read the rotation speed of fans or control their speed through software. The fans are powered directly by the power supply and will run at 100% the whole time.

If you connect them to the motherboard, the motherboard will at very least be able to read the rotation speed and at least for some connectors (depending on how high end the motherboard is) you may be able to control the fans through software or at the very least from BIOS.

 

There's no downside keeping the fans running at 100% all the time, besides the noise.  Also, in my humble opinion, it's very hard for me to understand why would you need 5 fans in your computer.

Modern components no longer produce that much heat and (except mechanical hard drives) also they don't mind staying much warmer compared to older generations of components.. most components would work just the same when hot compared to when they're much colder, so it makes little sense to make your system noisy just so you could see some low temperatures in the case.

 

For example, a video card will run just as fast and will function perfectly for decades at 70c or at 50c, no point in adding fans to a computer case just to move enough airflow to keep a video card colder than normal.

 

My advice would be plug the fans in motherboard fan connectors, if you don't have so many or they look ugly, buy yourself a 4-8 port fan controller and plug the fans in that fan controller.