Question can i connect 2Fan headers into 1Fan?

[Forol1561]

Hello so my motherboard can't supply my fanhub enought so i want to know if i can use 2 headers for more current flow

 

[punkncat]

No, get a fan hub that plugs into a molex or sata connector.

 

[Forol1561]

but then i won't be able to controll the speed's

 

[punkncat]

but then i won't be able to controll the speed's

The (for instance) Arctic fan controller:

Amazon.com: ARCTIC Case Fan Hub - 10-fold PWM Fan Distributor with SATA Power - Black : Electronics

It uses fan #1 IIRC to control speed on all fans connected to it.

 

[Forol1561]

so basicaly it will get power straight from powersuply and it will controll the fans based on motherboard input ?

 

[Karadjgne]

A fan hub should always be used with psu direct power, Never power from a motherboard header.

The amount of fan ports on the header is only consequential to the total power draw of the fans. Some older fans could pull almost 1A by themselves, so you would not use a 6+ port hub and plug all 6 fans into it, regardless of psu power because sata/molex is only rated for 4.5A.

More modern fans generally only pull 0.2-0.4A, so you could use a 10port hub with 10 fans and be safe.

There is only 1 control fan. That fan (#1 port) will have a 4 wire connection, just for the tach wire (reported speed). The rest of the fans follow its lead, so all fans on a hub will copy whatever speed the #1 fan is set to.

Most fans today have 4 wires. Power, ground, tach, Pwm. Power is a permanent 12v, can be from any source. Tach is reported speed, but PWM is the signal telling the fan how fast to go. #1 Tach says how fast the fan is spinning, cpu increases or decreases the PWM to make the fan spin faster or slower. That signal is split to all fans in the hub, so all fans get the same control signal.

 

[Forol1561]

yeah i know but i have DC fans in my case so that's the problem

 

[Karadjgne]

That's a problem lol. There's very few hubs capable of running and controlling DC fans, because they need a voltage adjustment, which the psu cannot do.

My last build using DC fans, I used a fan controller. It was a 5.25' and bolted right into the optical slot. Total of 3 channels was 50w capable, had manual or automatic control. Not easy to find today because nobody uses DC fans, too little control and too many power issues and do not work well with rgb.

 

[Forol1561]

i mean i could build one myself but it feels like it's not worth the time

 

[punkncat]

I haven't looked in ages for such, but there used to be a PCI card that would manage DC fans with a potentiometer. It wasn't "active", it was turn the dial.

 

[Forol1561]

i mean it would be quite easy to build one but idk if it's worth my time

 

[CountMike]

Hello so my motherboard can't supply my fanhub enought so i want to know if i can use 2 headers for more current flow

In theory yes, a simple diode in direction from each header's +12vdc to header, Diode so power from each header is isolated from each other, Fan's RPM sensor to only one header and negative can be common

 

[Karadjgne]

In theory yes, a simple diode in direction from each header's +12vdc to header, Diode so power from each header is isolated from each other, Fan's RPM sensor to only one header and negative can be common

You forgot about the ground. It's going to take the path of least resistance, not share itself equally, so stands a good chance of seeing the full amperage of both headers run through a certain amount of traces before it hits the ground plane.

 

[CountMike]

You forgot about the ground. It's going to take the path of least resistance, not share itself equally, so stands a good chance of seeing the full amperage of both headers run through a certain amount of traces before it hits the ground plane.

Ground doesn't need diodes, you can connect from both headers without anything else All is connected in one place on whole MB,. PSU and case, There are other connections that have separate .-12v, -5 and -3.3v but mot fan headers. For fans, lights etc you can even use case ground, MB is grounded to case thru standpffs and case is grounded to PSU too

 

[sajid_ali]

It's possible that using two headers to supply power to your fan hub could increase the current flow and provide enough power to your fans. However, it's important to check the specifications of your motherboard and fan hub to ensure that this is a viable solution.

First, you will need to check the current rating of the headers on your motherboard. Most headers on motherboards are rated for 1A (Amp) or less. If the headers are rated for less than 1A, then using two headers may not provide enough current for the fan hub.

Next, you will need to check the specifications of your fan hub to see how much power it requires. Most fan hubs require a specific amount of power to run, usually around 2-3A. If your fan hub requires more power than what the headers on your motherboard can provide, then using two headers may not be enough to power the fan hub.

Another thing to consider is that the headers on the motherboard are usually not designed to be used in parallel, which means connecting two headers together, this could cause issues with the power supply and could damage the components.

It's also worth noting that some motherboards have a built-in fan hub that can be used to power multiple fans, you might want to check your motherboard manual to see if this is the case.

 

[Karadjgne]

Ground doesn't need diodes, you can connect from both headers without anything else All is connected in one place on whole MB,. PSU and case, There are other connections that have separate .-12v, -5 and -3.3v but mot fan headers. For fans, lights etc you can even use case ground, MB is grounded to case thru standpffs and case is grounded to PSU too

That's not what I'm saying. Using 2 headers on a single load will increase the demanded amperage. That amperage will go somewhere through a ground path. It'll follow the path of least resistance.

So if Op has enough fan amperage to overdrawn a single header, requiring 2 headers, and is pulling more than 0.6A from each header, it's entirely possible all 1.2A will go back down 1 wire into the 1 header.

It's not just the mobo traces that are rated at 1A, it's also the header, pins, connections etc. If Op is using a header on a short wire, and the other header is on the other side of the board, you'll get mismatched draws, the short header seeing low amperage, the long header seeing higher amperage, and the reverse for the ground.

With DC voltage, the ground path is a current carrying pathway. The only difference between ground path and line path being potential, the ground limited by the load, the line limited by the psu and connections.