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Cooling Splicing Fans

Discussion in 'Hardware' started by sixfootsideburns, 27 Dec 2009.

  1. Zurechial

    Zurechial Elitist

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    I've done this quite a few times with fans and was always worried about the current involved.

    I contacted Gigabyte to ask them about it, and they helpfully told me that the fan headers on my motherboard (X58-UD5) are rated for up to 2A, so anything below that was safe.
    I thought that was a crazy figure at first, but I currently have 5x 120mm PWM fans daisy-chained and connected to a single header without any problems.

    I'd assume that the safe value is going to vary from one board/header/brand to another, so don't take it for granted, but that's my experience of it. :)
     
  2. Unicorn

    Unicorn Uniform November India

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    The short answer is no. The main reason is automated manufacture solder. The solder on the underside of motherboards is applied with a solder bath, at high temperature. Probably higher than the temperature of your soldering iron and definately higher than the plastic on motherboard fan headers can handle. You can tell I've tried this before, and it didn't work. Plus, the headers you get on a motherboard aren't enclosed like actual 3 pin fan connectors and they won't have wires on them, so they're not really suitable for what you're after.

    No offence, but you're thinking about this too much. It's just a simple 2-1 fan adapter, and again it's no problem for me to knock one up for you in literally 5 minutes and stick it in the post to you. There is really only one correct way to do it, and we've already told you what that is and what you need for it.
     
    sixfootsideburns likes this.
  3. IwantAbetterPC

    IwantAbetterPC What's a Dremel?

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    Hi Uni,

    I have a similar issue, where I want to daisy chain 3 fans on an XSPC RX360 onto one fan header of a ncubed T-Balancer BigNG fan controller. So if I understand you'd daisy chain 3 males into one female, with only the last male before the female carrying the yellow tach cable?

    ...or am I completely wrong :)
     
    Last edited: 13 Aug 2010
  4. Bloody_Pete

    Bloody_Pete Technophile

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    Not sure if anyone stated this, as my eyes ache too much to read everything, but its not the running wattage you need to worry about, its the starting wattage. Most fans need a massive boost in power to get them started. I found this out when I was looking at doing this for 3 Gentle Typhoon 1850RPM fams, which run at 1 watt each, but at startup they need 14 watts (combined from all 3). My fan controller can supply 12W per channel, so when the fans are up and running its ok, but the start up power wonder push over this every time I started my machine, which would blow the power feed. In a fan controller it'd just mean a less of a channel, but on a motherboard... Could be bad.
     
  5. joavery

    joavery Huh. So it CAN burn...

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    To make sure I understand this right - you can't control the RPM's of two Fan's connected together, only 1, correct? Or are you able to control both, it's just that the yellow wire is a sensor for only 1 of them?
     
  6. Bloody_Pete

    Bloody_Pete Technophile

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    The yellow wire is the sensor, but the RPM is controlled by varying the voltage to the fan, so you can change the speed of 2, just not monitor both.
     
  7. joavery

    joavery Huh. So it CAN burn...

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    Fantastic.

    Goodbye Hardware Fan Controller

    Hello Software Fan Controller
     
  8. Bloody_Pete

    Bloody_Pete Technophile

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    Hardware fan controllers are ok :)
     
  9. joavery

    joavery Huh. So it CAN burn...

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    Oh no doubt - but it's money I don't need to spend, I used to love Fan Controllers, but I'm a minimalistic kind of guy that loves doing things through software when possible. Especially because I want a clean front on my ATCS 840 : )
     
  10. Bloody_Pete

    Bloody_Pete Technophile

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    True, but I love my Scythe Kaze Master Ace, perfect balence of both :)
     
  11. IwantAbetterPC

    IwantAbetterPC What's a Dremel?

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    Thanks mate - hmmm - my fans too are Gentle Typhoons. The mCubed TBalancer says it's good for up to 20W per channel (X4), so I'm hoping that 3 onto one won't blow it, as I'll have another Gentle Typhoon plus another case fan and a 200mm side fan (case is a Cosmos S) all loading at the same time on the other channels. Might run it off a separate rail from the power supply, as the molex rail will be running two XSPC 750 Rev 2 pumps which will also need a jolt to get them going. Wish I'd never started this build now :)
     
  12. ataraxis84

    ataraxis84 What's a Dremel?

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    I know its already been said, but I think its always worth overstating......

    Be very carefull strapping multiple fans together onto a motherboard header, its not what they were designed for, and could result in damage to your board which in many cases is worth considerably more than a fan controller/internal multifan port.

    If it was me I would create the splice, but run the red and black to a 4 pin molex, and run the yellow wire from one of the fans to a male 3 pin to go to the motherboard header. That way you get your fan speed monitoring, but with a simple switch(if you feel adventurous) or just changing which way you wire it into the molex, you can change the fan speed from 12V to 5V without ever risking damaging your Motherboard.

    If you need any help doing this, I'm sure I can either find a guide or draw you a diagram. Also, I personally would use a terminal box to do the splicing, and run a slightly higher gauge wire into the molex.
     
    Last edited: 18 Aug 2010
  13. IwantAbetterPC

    IwantAbetterPC What's a Dremel?

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    That's a good idea! I was worried about having to disable the CPU fan detection in the BIOS (all watercooled), as all the fans will be running off the TBalancer unit and not the motherboard, but running a yellow back to the CPU fan header should mean I can leave the setting active. Sweet!

    Craig...
     

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