Will I blow up my Mobo with this fan mod?Help!?

[monkeyboy2323]

I'm currently running one 80mm 12V fan (thermaltake) at the back of my case(and one at the front) off the 4 pin 12V PSU connection. I want to run 2 fans in series off the same 4 pin connection (so that they are 2x 6V fans for noise reduction purposes) but will my Epox 8RDA+ be able to handle this mod or will I run the risk of melting my shiny new motherboard?

 

[GAZZA]

Your connecting these to a molex plug off your psu right ?
Then you have nothing to worry about, at first I thought you were talking about connecting those fans to the fan headers on your motherboard , then you probably would have blown the fan headers for sure.

 

[Hazer]

Melt your motherboard? Fist off, I dont think you have anything to worry about your motherboard overheating (unless your system has serious issues).

You can run the fans in series, but I can tell you right now, most fans shut-off at 7V. They probably wont even spin.

If you want to cut down the voltage, just put a resistor in series with your 12V line:

If your fan is say 0.14Amps, you find the resitance by 12V/0.14A = ~85 Ohms. You then calculate the series resistor by (12V)(85 Ohms)/(85 + R) = Vwanted.

So for Vwanted = 7.5, R = ((12V)(85 Ohms)/(7.5V)) - 85 Ohms = 51 Ohms.

Since the current flowing through the resistor will be 88mAmps, you will need a 1/2Watt resistor. (4.5V across resistor * 0.88A = 0.4 Watts).

This is the quick and dirty way to cut the voltage of a fan. There's better ways but they require transistors which you may be better off just getting a $15 Rheobus.

Oh Snap! I forgot! You can easily get 7V by moving the pins around on your Moolex connector! Yellow wire is 12V, and red wire is 5Volts. Plug your fans ground wire into the 5 Volt red wire and you get a 7 Volt drop across your fans.

 

[monkeyboy2323]

Thanks for the info. It looks like the 2 fans in series thing is a no-go then......I've heard that the 7V mod on the 4 pin has some potential inherent PSU related risks. Is this the case to your knowledge(360W thermaltake silent PSU)??

 

[eklass]

catch fire? maybe. blow up? uh hell no