Connecting 2 PSUs Together?

I noticed the Corsair 900D case has room for 2 PSUs. I like the idea of using a pair of ax860s or Seasonic Platinum 1000s to power something like a custom water cooled, quad GPU rig.

What would be the best way to do something like this? You would obviously have 1 PSU connected to the motherboard but I'm assuming there is a more elegant way to start up the second one than bridging it with a paperclip. If you solder the 2 start wires from one PSU to the other, the power button would start them both simultaneously correct?

Are there any concerns regarding potential damage to hardware? I'm thinking you could use one PSU to power 3 of the 4 video cards and the other to power the rest of the system.

If you have experience with this or have any suggestions I'd love to hear your thoughts.

Thanks

What would be the best way to do something like this? You would obviously have 1 PSU connected to the motherboard but I'm assuming there is a more elegant way to start up the second one than bridging it with a paperclip. If you solder the 2 start wires from one PSU to the other, the power button would start them both simultaneously correct?

The easiest way is to use something like this product here

http://www.frozencpu.com/products/5637/cpa-167/Lian_Li_Dual_Power_Supply_Adapter_Cable.html?tl=g2c413s1220

And yes, they will both start with the push of the case button.

Are you looking for redundancy or increased power capabilities?

Turning on two power supplies at the same time, as the Lian Li adapter does, may be good for powering external devices like disk readers, hard disks, etc. from an alternate power supply but it would not be good for feeding things that are on or connected to the mother board like GPUs, etc. The reason is that the power supplies would never have exactly the same output voltages and, therefore, would be bucking each other all the time.

Also, this adapter doesn't create redundancy.

The reason is that the power supplies would never have exactly the same output voltages and, therefore, would be bucking each other all the time.

No they wouldn't . People use dual PSU's to power multiple GPU rigs all the time. The card or devices will do what they need with the power. All your feeding to GPU's is he 12v PCI cables. What ever power they require from the MB they would still get.

It's no good for redundancy, but if you have a rig thats going to use more than a 1200W PSu then dual PSU's may be what you need.

Thanks for the info. I'm looking for increased power capability with the additional PSU. It sounds like it will do exactly what I want.

Thanks for the link to that Lian-Li adapter. That's exactly what I'm looking for. Saves me the hassle of having to solder the wires.

There are multiple ways to do this. There is a way to offer redundancy and increased power availability to devices and there is a way to just add a PSU to power some of your fans, pumps, GPUs, ETC.

If all you want is more power for GPUs and other components then ALL you need is just a single bosch automotive relay. You will trigger the relay from a 12V molex and you will use the relay to short the 2 wires that you normally jump to turn on a PSU without a motherboard. That is all you need. I said bosch automotive because they are extremely easy to come by but there are tons of smaller relays out there that will do this. The relay doesn't need to be able to handle any real current which the bosch is made to handle plenty of current so it is def overkill but regardless start from there if you want smaller find a smaller one.

There are multiple ways to do this. There is a way to offer redundancy and increased power availability to devices and there is a way to just add a PSU to power some of your fans, pumps, GPUs, ETC.

 

If all you want is more power for GPUs and other components then ALL you need is just a single bosch automotive relay. You will trigger the relay from a 12V molex and you will use the relay to short the 2 wires that you normally jump to turn on a PSU without a motherboard. That is all you need. I said bosch automotive because they are extremely easy to come by but there are tons of smaller relays out there that will do this. The relay doesn't need to be able to handle any real current which the bosch is made to handle plenty of current so it is def overkill but regardless start from there if you want smaller find a smaller one.

Thanks for the info. Are there any advantages to the bosch automotive relay over the Lian-Li adapter peanutz94 linked above? I already ordered one of the Lian-Li adapters earlier today to test out.

Just out of curiosity, if you're using two identical PSUs what happens if you power a video card with one PCI-E cable from each PSU? If the voltages are slightly different between the two PSUs will it damage the video card?