how much power to my fan header?

bazpaul

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Oct 24, 2013
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Hi guys, I searched on gigabytes manuals but no dice!

Can you tell me the power or current (amps) that the fan header on the GA-Z77n-WIFI supplies?

I want to run three fans using a fan splitter from the one fan header - can I do this?

I want to run 2 140mm fans at the back of the case and 1 230mm fan at the front on the case.

see here http://screencast.com/t/cz9NuZW50Tt

or this link http://www.bitfenix.com/global/en/products/accessories/spectre-pro-led#specs

I have a 550W power supply and a Bitfenix prodigy case

Thanks very much
 

Karadjgne

Titan
Herald
Pretty much that's exactly what I mentioned earlier. What Akasa has done is taken the pwm control wires and separated them from the power wires for you. With that adapter you can power any 4 pwm fans from the psu directly, while maintaining control of speed through the mobo header. I would recommend using identical fans though, because the pwm will read the speed if the fans through just one, using the other three as mules. If using mismatched fans, the speeds will not be read correctly, so either under spinning or over spinning the ones not being directly controlled. Basically your pc will recognize the header as a single fan.
 

makkem

Distinguished
Hi
It is remarkably difficult to get this information generally,some motherboard manufacturers quote it and some don't,all I can say is that generally the headers can support about 20W.
140 fans take about 2W and 230 fans about 3W so it should be well within the capabilities of your motherboard to support the fans you want to fit.
If you are still concerned you could fit a fan controller as these run from a molex.
 

Karadjgne

Titan
Herald
Depends on the draw of the fans. A fan header will supply aprox 0.8-1.2 A, which is usually sufficient topower 2 fans with a little headroom.

My Noctua NF-F12 has a draw of 0.18A so I'd be confident putting 4 in line on a double radiator, however there are some high cfm fans that draw 0.6A+ so I wouldn't recommend using more than 1 per header.

It's not uncommon to hijack the speed sensor wire for 3-pin or even the pwm control wires and using those on the header, while using a Molex or sata connector for the power supply for multiple fans, but that could mean some creative soldering/re-pinning.
 

bazpaul

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Oct 24, 2013
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Thanks guys!

Gigabyte got back to me and said that my header has a max amperage of 1A.

Now based on the current on the fans in my post - do I add the current together so - 0.25A + 0.25A + 0.41A = 0.91A

This is just below the 1amp........hmmm

also you said;

""It's not uncommon to hijack the speed sensor wire for 3-pin or even the pwm control wires and using those on the header, while using a Molex or sata connector for the power supply for multiple fans, but that could mean some creative soldering/re-pinning. ""

I was thinking about this - can I power a number of fans using molex but control their speed from my mobo? I would love to read more about this if you have links - thanks

 

makkem

Distinguished
Hi
I have not tried this but in principle you should be able to do it.
You would need to cut the yellow wire of the fan(s) cable so disconnecting the +12V from the motherboard and then connecting a +12V feed from the yellow wire of a Molex and splicing in a 0V black molex wire to the black on the fan cable.
I would be interested to know if anyone has tried this in practice.
 

Karadjgne

Titan
Herald
Sure, been done many times. 12v is 12v, no difference as the connectors are all joined to the same source rail (s) anyways. By doing something like that and just leaving the pwm or speed sensor wires intact, all you are doing is removing the 1 amp restricted source headers and resupplying with straight psu source. Of course pwm fans will still be controllable, whereas the 3 pin won't, as the source is now the psu not the mobo.
 

bazpaul

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Oct 24, 2013
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Thanks guys,

I'm nervous about disconnecting cables - plus i dont own a soldering iron :)

I found this online and i think i'm going to buy it - http://www.ballicom.co.uk/akcbfa0345-akasa-flexa-fp5--fan-power-splitter--4-pin-pwm-f--4-pin-internal-power-4-pin-pwm-m--45-cm.p706686.html?ref=PLA&gclid=CNeE5rjckr8CFQ2WtAodpUwAJg

Would I be correct in saying this company Akasa have wired all the power sources to be taken from the molex rather than the header?

I'm paranoid of burning out the header on the mobo

Thanks guys
 

Karadjgne

Titan
Herald
Pretty much that's exactly what I mentioned earlier. What Akasa has done is taken the pwm control wires and separated them from the power wires for you. With that adapter you can power any 4 pwm fans from the psu directly, while maintaining control of speed through the mobo header. I would recommend using identical fans though, because the pwm will read the speed if the fans through just one, using the other three as mules. If using mismatched fans, the speeds will not be read correctly, so either under spinning or over spinning the ones not being directly controlled. Basically your pc will recognize the header as a single fan.
 

bazpaul

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Oct 24, 2013
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Thanks, thats what I was starting to think.

Grrrr......today as I write I just recieved my Bitfenix Spectre Pro 230mm for the front - and I already have 3 x 140mm fans for the back.

Any advice on the best configuration?

Option 1 - Read the pwm speed through the large 230mm fan - thus the 3 exhaust fans will run slower.

Option 2 - Read the pwm speed through one 140mm exhaust fan - thus the large 230mm could run faster. (But its a larger fan so when its faster its quieter than the same speed of a small 140mm, right?)

option 3 - I could possibly create a custom speed fan profile with my setup in mind?

Option 4 - Sell the 230mm on ebay and grab two 140mm (would rather not do this as I really want a large 230mm)

Cheers


 

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