SOLVED Validate Fan Setup

[mrd]

Hi everybody,

After my recent embarrassment with 24V fans I beg for assistance with my next purchase options. I plan on getting these 2xNoctua nf-f12 iPPC 3000 (used as intake) and 1xNoctua nf-a14 iPPC 3000 fans (outtake), together with this splitter and extension cable. They'll be connected to my mobo's FAN-A header, which

Show : according to the manual

handles up to 2.5amps. The fans are rated for a total of 1.15amps, so everything should be fine.

Right? right?.... :(

 

[Dice]

Looks good.

 

[mrd]

Anyone else care to sign off on this?

 

[danpoleary]

I have seen issues where the peak start amperage of the fans can exceed what the motherboard supplies. In most cases, this short spike is allowed, but this depends on the components on your board. I believe the max peak on most fans during start is limited to 2 amps, with a 1 amp avg limit for a 1 second duration.

 

[Stux]

I have seen issues where the peak start amperage of the fans can exceed what the motherboard supplies. In most cases, this short spike is allowed, but this depends on the components on your board. I believe the max peak on most fans during start is limited to 2 amps, with a 1 amp avg limit for a 1 second duration.

I *think* the noctua fans have a slow start to avoid this, but you'd want to check

 

[Dice]

I wouldn't worry about that.
If you really want to fix that, you can always chop a molex extender cable, and pull power directly from the PSU but maintain the RPM and PWM signals to the motherboard for control.
I ran this type of setup with great success when having 6x heavy duty fans..

 

[Ericloewe]

I have seen issues where the peak start amperage of the fans can exceed what the motherboard supplies. In most cases, this short spike is allowed, but this depends on the components on your board. I believe the max peak on most fans during start is limited to 2 amps, with a 1 amp avg limit for a 1 second duration.

Since this case is a Supermicro motherboard, I'm willing to assume they allow for spin up current for insane (8k RPM insane) fans.

 

[mrd]

Since this case is a Supermicro motherboard, I'm willing to assume they allow for spin up current for insane (8k RPM insane) fans.

I can't seem to find a review that does an indepth analysis, but these guys claim that the 120mm fans (rated at .3 amps) drew a max of ~.2A. That was probably during their tests though...

 

[danpoleary]

Since this case is a Supermicro motherboard, I'm willing to assume they allow for spin up current for insane (8k RPM insane) fans.

Supermicro pwm supports a max peak of 3 amps per connector. As long as total startup amperage does not exceed that, then your fine. but like Dice said, you could use connectors from power supply while maintaining the pwm to motherboard. They sell adapters for this if you don't want to make your own.

 

[mrd]

They sell adapters for this

Got a link perchance?

 

[danpoleary]

Got a link perchance?

Here is one: http://www.aquatuning.co.uk/cables/...n-molex-auf-2x-4pin-pwm-und-3pin-30cm-schwarz
and another: https://www.amazon.ca/Splitter-Molex-headers-CONNECT-MULTIPLE/dp/B009D3HV1Q

 

[mrd]

Here is one: http://www.aquatuning.co.uk/cables/...n-molex-auf-2x-4pin-pwm-und-3pin-30cm-schwarz
and another: https://www.amazon.ca/Splitter-Molex-headers-CONNECT-MULTIPLE/dp/B009D3HV1Q

Is there any chance to overload this connector instead of the mb header?

 

[Ericloewe]

Most Molex connectors are rated for at least 6.5A, so you'd have a hard time. Unless of course you buy a dual 80mm counter-rotating fan rated at 130W and 10k+ RPM.

 

[danpoleary]

Is there any chance to overload this connector instead of the mb header?

On a Corsair RM850 power supply, the 12 volt rail is rated at 70.8 amps. Each power supply is different, and should be labeled on the power supply itself. I am not sure of the per molex rating, but I believe its 11 amps.

Edit: Yes, confirmed that the molex connector is rated at 11 amp/pin, with 18 gauge wire up to 10'

 

[mrd]

Will this splitter feed RPM speed back to the motherboard (as far as the pics go, I don't see any 4th pin on any of the fan heads)?

 

[danpoleary]

Will this splitter feed RPM speed back to the motherboard (as far as the pics go, I don't see any 4th pin on any of the fan heads)?

That one does not, this cable powers 2 x 4 pin fans and 1 x 3 pin fans, and passthrough for 4 pin molex.

This one: https://www.amazon.ca/Splitter-Molex-headers-CONNECT-MULTIPLE/dp/B009D3HV1Q connects 3 x 4 pin fans controlled by one PWM connector on motherboard, but no passthrough on the molex.

More details on this item here: http://www.cablematters.com/pc-811-119-2-pack-pwm-3-fan-splitter-cable-with-molex-power-1-foot.aspx

Note that only one of the 3 fans is monitored, you cannot monitor more than one fan per PWM connector. So if all three fans are the same, only one is monitored but all 3 will be controlled.

 

[mrd]

More details on this item here: http://www.cablematters.com/pc-811-119-2-pack-pwm-3-fan-splitter-cable-with-molex-power-1-foot.aspx

Note that only one of the 3 fans is monitored, you cannot monitor more than one fan per PWM connector. So if all three fans are the same, only one is monitored but all 3 will be controlled.

That's what I was looking for. Now just need to find it in Europe. Thanks a lot.