How To Use Three PSUs In One System

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While we have a full review of the new Add2PSU adapters coming soon, I just had to share this video with you guys. The idea has been around for awhile (remember this?) but has been refined into a true plug & play way to add up to two PSUs to your existing system. This could be really handy for all you guys running power hungry systems with water cooling, added hard drives, lots of fans and so on.
 
Video makes it look really easy to setup a couple psu's.

I think I will wait for the [H] review before I actually go out and buy another psu :D
 
First step: upgrade your hour wiring to deliver 40+ amps at the wall (33.3A at 120V = 4kW, or three 1200W PSUs with 90% efficiency). :eek:
Second step: Call the power company and police to let them know that you are NOT growing cannabis. :p


In all seriousness, what do you need two or three PSUs for if you can buy 1200W, 1500W, or even 2kW PSUs?
 
Yeah, I kind of have to agree with the comment on Youtube. Why spend $20 apiece on these when you can just splice two wires? Or get one of those splitter cables like kevinugenius posted above...probably could be found for less than the $15 it is on that site.
 
MavericK96 said:
Yeah, I kind of have to agree with the comment on Youtube. Why spend $20 apiece on these when you can just splice two wires? Or get one of those splitter cables like kevinugenius posted above...probably could be found for less than the $15 it is on that site.
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Because people will buy it..
 
Seems like a better solution than some psu adapter cable setup which has to go between the motherboard & the main psu, which limits one to 2 psus, this can allow up to 3 psus. And yes I like it, Not bad for $21.98 total for one adapter, for two It sounds like maybe $41.97, but then one is paying for that big black relay, the board and the connectors, not to mention someone had to assemble them. :)
 
Why do you even need that much power?

Stuff should be using less power as stuff get smaller not more!
 
This is something that needs a LONG TERM TEST done on it. Sure it might work today.. tomorrow.. a week from now.. but will this be digging an early grave to some or all of your PSUs plus MB/video cards/hard drives over time? Also wonder if this device has any negative effect on the energy efficiency of the PSUs.

Would be interesting to see a comparison done on two rigs set up with the same MB/CPU/SSD/Video but have one with a 1200W PSU and another with two or three 600/700 PSUs. And also a test with a rig running something stupidly ridiculous like quad 590s, EVGA Classified SR-2 with dual overclocked CPUs and more than a few spinning hard drives, some monster system that sucks up over 1000 watts while idling!

psu_fire.jpg
 
back in the P1 days with my Yamaha CDR100 and SCSI drives two power supplies were necessary... all I did was fire off the 1st power supply from a switch for the drives and let them spin up before the main board power supply ( worked like a charm )
 
The device is probably a simple relay that does the same thing as shorting the two pins you need to jump start the second psu(s). I can't see it being any more or less reliable than the splitters or manual methods, unless they used a defective relay. I'd considered building one of these at one point, but never needed one long term. I do prefer this design over the 24 pin splitters for the sake of cable cleanliness.
 
I would like to see the results of having a gtx580 2 x PCIe power supply's coming from 2 separate units
 
Mad Cat said:
First step: upgrade your hour wiring to deliver 40+ amps at the wall (33.3A at 120V = 4kW, or three 1200W PSUs with 90% efficiency). :eek:
Second step: Call the power company and police to let them know that you are NOT growing cannabis. :p
Click to expand...
Could be worse like me with a reef tank with corals, with the metal halide lamps, high power consumption oddly bright glow coming from the house... :D

That said I wonder how much power it takes just to keep a power supply on for the sake of having extra power ready should you need it.
 
I put together a quick (somewhat ghetto) adapter that appears to be similar to this for a system where I needed more power to drive a fairly large cooling unit and a 6 disk raid 5 array at the same time (hmm is it redundant to say disk & array when using the term raid... oh well). This was back when 1k PSU's were not common and 100GB drives were the largest available (so a while ago). Just a quick look at the components make it appear to be the same. For those that did not check out Steve's 2nd link, the concept was to take a relay and connect it to the molex of the Master PSU, then use the relay to trigger the Slave PSU to turn on via an ATX power connector so that the original wiring harness of the Slave PSU did not need to be modified. There was one main caveat to it though. Most power supplies that were out at the time needed a minimum power draw on all of the rails, only a few power supplies did not require this (the Antec True series is what I had used since each rail was setup independently and had a min load of 0A). Since most users of this will only draw power typically on the 12v and/or 5v rail, the 3.3 volt rail will go unused. So if the power supply has a minimum load on a rail you are not using make sure to put a load on the rail(s) or just get a PSU that has a min 0A requirement on the rails you won't be using. A quick look at a random PC P&C PSU tech spec still has the min load per rail published. The one I happen to look at had minimums of 12v @ .3A, 3.3 @ .5A, 12V @ .9A, , -12V @ 0A, & 5Vsb @ 0A. One last thing to be aware of is unintentional grounding loops that can occur when mixing & matching leads from the different PSU's.
 
[Edit] CoolerMaster sold these with their towers years back.... to connect 2 PSU's together.
 
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Grounding the green wire on your ATX connector completes the circuit and powers up your PSU.

No it's not going to destroy anything, FFS.

They're just using the molex ground from PSU1 to jump the green wire on PSU2&3.
 
I laugh when when ever I hear the term "and USE MOAR BIGGER VIDEO CARDS!!"
 
Interesting and sort of cool to be able to do that, but I don't really see the "value" or point in doing it, since any high-end, high-watt PSU can handle any amount of drives, fans, GPUs etc. these days.
 
Trimlock said:
I laugh when when ever I hear the term "and USE MOAR BIGGER VIDEO CARDS!!"
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Would You laugh if I said I was doing Radio Astronomy? Cause that is what Seti@Home essentially is, so 6 GTX295 cards will be used for CUDA tasks, not more video, as the drivers don't support more than 4 gpus for video, for cuda tasks this is only a power problem and yes I have the motherboard, the blocks and a used HAF-932 case.
 
When I see stuff like this, I can't help but think that a computer with 3 1200W power supplies would have more horsepower than my lawnmower and chainsaw combined.

Almost a 5 horsepower computer... :eek:

Don't forget to add in the cost of wiring in a 240v / 30A outlet to power your computer.
 
Bdbtoys said:
One last thing to be aware of is unintentional grounding loops that can occur when mixing & matching leads from the different PSU's.
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What kind of damage can this cause?
Also, is there any risk in using say, like in the setup from the video as an example, using the 24pin ATX connector from PSU #1, 8/4pin 12v connector on PSU #3, and the 6/8pin PCIe connectors on PSU #2?
 
Does it come with a fire extinguisher? Just seems like a bad idea... Now a days there are large enough PSUs to power the most demanding rig. Why would you need to hookup 3 PSUs? Worthless IMHO.
 
If you can find a computer case with enough space, fan holes and screw holes for 3 PSUs, it probably comes with the 3 PSUs already, and all the connectors.
I think it's worthless for cheap 400W PSUs, it costs only 70% or $80 less compared to a single 1200W PSU looking at Corsair prices. True, it's cheaper to replace a single defective 400W PSU and you can reduce costs even more by purchasing cheaper PSUs for non-essential devices such as neon lighting.

I'd probably restrict the device's usage to when you need more than a single 1200W PSU (and 2 such PSUs should be plenty for anything you can throw into a single computer case.) I am more interested by computer cases that allow the PSUs to work in parallel for redundancy, not just in series, or by PSUs that are designed to safely power say 24 hard disks in addition to the motherboard and normal devices.
 
Wait, you mean I can spend $22 on a PCB that contains one molex connector, one atx connector, and one cheap 12v relay?:D Ohh boy, sign me up! :rolleyes:

I also agree with the earlier comments about the need to have more than one PSU anyhow.

The things we did in the golden age of computing with PSUs is so we could:
A; Buy decent but less expensive PSU's.
B; Add redundant supplies in case one failed in a mission critical situation.
C; 1000w PSUs were not available and some machines required that much to run all the HDDs.

Also brought up. Most household circuits can supply a MAX of 1800w. Really more than 1500w and your pushing it. Not talking about just the outlet either. There is usually more than one wall outlet on the circuit.

Man this just screams bad idea.
 
BallerX said:
Also brought up. Most household circuits can supply a MAX of 1800w. Really more than 1500w and your pushing it. Not talking about just the outlet either. There is usually more than one wall outlet on the circuit.

Man this just screams bad idea.
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Indeed... Last time I was home, we tried to run two A/C units and two desktops off the same circuit. We could only do one A/C and one desktop before the breaker would go. :(
 
I'm really not sure what there is to "review" about a board that switches the PS-ON line of a PSU when it sees power on a molex connector.

Why anyone would use a relay for this (as seems to be done in the picture) is a mystery to me though, relays are relatively expensive and not particually reliable, a small jellybean transistor (e.g. a 2N3904) with an appropriate base resistor would be just fine.

If you wanted to be really neat you could get a fully modular PSU and replace the ATX cable on it with a custom chaining cable containing the transistor and resistor. That way you'd avoid having to deal with the bulk of the second ATX cable. Sadly because afaict there is no standard for modular cables you would have to custom make such a cable for a particular PSU.
 
handy, but it's not like it's that hard to piggyback power supplies together. Although if it's cheap it's probably easier to make this look clean.
 
TheBuzzer said:
Why do you even need that much power?

Stuff should be using less power as stuff get smaller not more!
Click to expand...

I really don't see a need for this especially with 1200 watt power supplies available

It's more of a problem finding an efficient low wattage power supply.

The HTPC I recently built draws less than 40 watts at idle, and less than 60 when recording 2 channels while watching a 1080p bluray rip at the same time. And this is with the cheap inefficient 500 watt power supply that came with the case. If I could find a reasonably priced 150-200 watt ATX 80+ power supply, I could knock another 5-10 watts off those numbers.
 
Yeah. 3 of these.

I'd need extra long cords to connect each PSU to a different breaker for each PSU. But hey.

;)
 
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