How does a dual PSU work?

[The Law]

I'm not really in the market for it but it interests me more than it should. So, how does it work?

[tryphaa]

You use the connectors from both psu's, then plug them both into the wall. Very simple.

[jscho]

Are you talking about the dual redundant PSUs you find in servers or having two full PSUs in your system?

[quan289]

You press the power button on the computer, and a signal is sent from the motherboard to the PSU via the green wire on the 24-pin connector.That's how the PSU is turn on to supply power to your system.

So basically, if you want the second PSU to turned on, you need to have that signal sent the other PWR_ON green wire as well. You can get an adapter or make one yourself.

 

Once you have done that, one PSU is supplying power to your motherboard, CPU, RAM, PCIe slots, etc. and the secondary PSU typically is powering the GPUs and such.

[NInety]

It's like a single PSU... but there's two.

[JupiteL]

It's like a single PSU... but there's two.

OP please make this the best answer.

[NInety]

OP please make this the best answer.

But... that's the answer, it's not rocket surgery, you plug stuff into either PSU.

[quan289]

But... that's the answer, it's not rocket surgery, you plug stuff into either PSU.

Well, it's certainly not rocket surgery, but it's not always as simple as plugging stuff into either PSU. Getting a CX430-600, EVGA NEX650G/750G, Seasonic S12II/M12II 430-630w, etc. as the secondary PSU can cause complication due to the design of the PSU, as you are putting the PSU in a crossload scenario where the voltage of the +12v rail would severely drop. This would negatively affect the stability of the system.

 

When doing a dual PSU setup, you need to make sure it is an DC-DC / indy regulated PSU.

[scaryjam823]

But... that's the answer, it's not rocket surgery, you plug stuff into either PSU.

I hate when I do surgery on rockets... It's like man why can't you be a kangaroo instead.