Fan Setup 5v/12v?

[johnboy1998]

Hi guys!

I am having a small problem with some fan setup here, ok so I just bought the following:

3 x Zalman ZM-F3 120mm fans
2 x 1 molex to four fans adaptor

Ok so my HAF 932 also has the 3x 230mm fans and the 140mm fan, so there will be 7 fans connected via the adaptors directly to the PSU!

The adaptors run two fans on 12v and two on 5v, so I want to run the three Zalmans with there 7v resistors on so these will connect to the adaptors 12v plugs!

But I presume if I run the the four stock HAF932 fans off the 5v s they wont run at the rated 700rpm?

I could run all the HAF932 stock fans from 12v and the zalmans on 5v?

p.s I had planned to custom wire all the fans to two seperate molex, but my molex crimper has dissapeared!

Any ideas/similar scenarios? thanks!

 

[MattNo5ss]

Hi guys!
But I presume if I run the the four stock HAF932 fans off the 5v s they wont run at the rated 700rpm?

I could run all the HAF932 stock fans from 12v and the zalmans on 5v?

The rated RPMs are usually based on 12v power, so your HAF fans will run below 700RPM if on 7v/5v.

I have one of those 7v Zalman fan resistors on my Panaflo which is runs at ~2800RPM 12v and with the 7v resistor connected it runs at 960RPM. Reduced the RPM a lot more than I thought it would, but my system is silent

Also check the starting and operating voltages of your fans b/c 5v might not be able to start or run your fans.

 

[bing]

Also check the starting and operating voltages of your fans b/c 5v might not be able to start or run your fans.

Agree, but if you have the "right" fan controller, for those that can't be started at low volt like 5 V, from my personal experience on various brand, 7 out of 10 of them will run smoothly at low volt if the fan controller can kick start them at 12 volt intially, and 'gradually' decrease the volt until it reached like 5 volts. Since its already spinning, that low voltage merely maintain the spin inertia.

 

[trents]

Why don't you install a drive bay fan controller to manage all those fans?

 

[Daddyjaxx]

You really don't need to manage the 230mm fans. They are quiet enough on their own at 12v.

 

[JCMAN]

I have a 120mm 12V 0.4A DC fan that I pulled from an old Dell desktop PC case. I powered it with a typical USB phone charger (5V 1A) thinking that the fan would run slowly. Instead the fan is running very fast and generating quite a bit of wind. Sorry, I cannot define what's considered slow or fast here as I don't have a tachometer. I thought this was due to the wattage being similar. But I have another 80mm 12V 0.18A DC fan that I connected to the same 5V 1A phone charger. That runs very quiet and the speed is slow, generating hardly any breeze. If the wattage was the cause, 80mm should run super fast. Does anyone know?

 

[Flamethrower1972]

I have a 120mm 12V 0.4A DC fan that I pulled from an old Dell desktop PC case. I powered it with a typical USB phone charger (5V 1A) thinking that the fan would run slowly. Instead the fan is running very fast and generating quite a bit of wind. Sorry, I cannot define what's considered slow or fast here as I don't have a tachometer. I thought this was due to the wattage being similar. But I have another 80mm 12V 0.18A DC fan that I connected to the same 5V 1A phone charger. That runs very quiet and the speed is slow, generating hardly any breeze. If the wattage was the cause, 80mm should run super fast. Does anyone know?

There is a difference in current but it's not a lot. I could be wrong.