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Dual PSU's and cooling...

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Feb 28, 2001
When i set up my water cooling system i was thinking of using 2 PSU's.

1 to run my mobo/CPU and peltier and 1 to run my case fans, radiator fan and drives. The reason is so i can set MBM to shut my system down if i am away and the temp rises above a certain threshold due to pump failure or whatever else.

I'm assuming my 300W power supply would supply enough watts to run the mobo/cpu and peltier (my 152W peltier is rated @ 15.6V am i right in thinking that a lower voltage, i.e 12V will still run it but at a reduced wattage?), and this PSU would shut down the peltier along with the mobo/cpu courtesy of MBM.

Now ive never ran a PC with a 2nd PSU, so have i got it all wrong there as ive just attched my fans to the 2nd one and they wont run.

Do i have to short the mobo connector on the 2nd PSU somehow to get it to run a voltage through the 4 pin 12V connectors?

Big thanks to everyone who's offered advice so far, and big thanks for the future as i have lots more questions.

wal :)
The pelt will draw about 120W at 12V.

Not sure about the second PS. There are some write-ups about using such a set-up on the main page. From what i understand it is best to mat an atx ps with an AT PS, which can be found very cheaply. There is a way to join them by connecting a few wires, so that they start up and shut down together.


for dual atx psu's join the green one to a black one, but how do you get an at one to work?