Dual PSU??? is it possible?

By SOcRatEs ยท 9 replies
May 3, 2005
  1. I have a 425 max watt & a 350 max watt.
    I would love to set my Sata drive as stand
    alone on separate PSU while still cabled to MoBo.
    I think the extra psu would have to be outside sys box n/p.
    I'm hesitant to try as yet because both psu's would need
    to power up simultaniously...
    I'm not sure how to configure the [power on] in the axt
    20 pin on both psu's.
    Any idea's? I'm might just be board
    THnx!!! :cool:
  2. Chesta1485

    Chesta1485 TS Rookie Posts: 16

    Not sure how that would work out, I would start seachin google with 'dual psu' see what happens. (thx for your replys in my post)
  3. RealBlackStuff

    RealBlackStuff TS Rookie Posts: 6,503

    WHY would you want to do that?
    The output of that 425W PSU should be enough, unless it is made by some obscure company, that glorifies the max power as sustained power.

    Please give us the make/model/specs of that PSU.
    But the hassle you'll be getting is hardly worth it, and I doubt that it even is possible.
    Getting a new more powerful (if needed) PSU from a reputable company would be easier by far.
  4. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    I fail to see the point of this but if you insist..

    Just look at the pinout of the ATX PSU connector (that is if you have standard ATX PSUs). Connect the power on wires (green) of both PSUs together and then to the motherboard. The PSU(s) will turn on when the power on wire is grounded inside the motherboard.

    Make sure that the PSUs have common ground. Better connect them to the same extension cord. and make sure the thing outside has good contact with the computer case.
  5. SOcRatEs

    SOcRatEs TechSpot Paladin Topic Starter Posts: 966

    Thank you!!

    My main psu
    430 Watt ATX12V
    Secondary for x-tra fans
    300 Watt ATX12V

    Most of this wild idea comes from having several psu's ly'in around.
    some of (too much time on my hands). :confused: I already run two psu's. one outside of my box, I never tried linking them together for key sys componants. mixing the power to drives cdrom's etc. from two psu's
    I always startup the fans separatly first then the system. lots of fans hit psu hard.
    I'm pretty sure it's a waste of time & bigger risk to link them...tho I wouldn't mind finding a way to make use of older out dated hardware...
    Thank you
    It's nice to have a place to wonder out loud.
  6. SOcRatEs

    SOcRatEs TechSpot Paladin Topic Starter Posts: 966

    Well it worked!

    Here is diag, as stated above by "Nodsu"
    thank you!
    Others suggested a dummy load but I did'nt need it.
    I'm only running my fans separately from other componants.
  7. kol_indian

    kol_indian TS Rookie Posts: 316

    could u tell me how u run the fans seperately i need to run the two extra fans that i have plus an old psu i tried a y connecter but i doubt thay will be good on the long run \

    please do let me know

    i dont want to connect them to the motherboard as it may be risky
  8. SOcRatEs

    SOcRatEs TechSpot Paladin Topic Starter Posts: 966


    Yes I'd be glad to try explainin it...
    It is quite risky play'n around like I have. Kinda like some of the postings here
    about over clocking. They give very good advice that we may be being cheap to over clock rather than, saving the grief and buying better equipment.
    I never do any over clocking, I just don't understand e-nuff and won't risk my systems.

    E-nuff of that!

    I first ran an old AT (250w)psu that I could turn on with power switch.
    I would switch it on first then hit the atx switch on front of my system.
    I simply ran my fan connectors out the back to spare psu (which used same power connectors as HDD, the 4 wire blk 2x, red and yellow)tho not ones accually connected to HDD's. All the wire splicers from fans were long e-nuff to reach outside my box. Kinda like setting a house fan next to sys and pointing it at the MoBo, with side panel off. What I have successfully done now, is to have 2 atx psu's inside my box, both turning on with one push of front panel button.

    It is critical to have both psu's mounted to same box frame using the same black wire ground splice (everything grounding to same place) and green wire 14 splices (solder only! twisting and tape can cause accessive heat). I also use a belkin power authority II: FSC140, so that both psu's are drawing power from same source and conditioned properly the same....

    I don't mix the power connections between HDD,CDROM,VIDEO etc. with the fans source.

    Again please be very aware the risk is greater than I thought, mixing two diff PSU'S (even if same make and model) should one ever "fail" (mostly the one powering the fans) or "GF" ever short out, you'll end up letting all the pretty blue smoke out and nuthin will ever work again.....LOL poof :hotbounce
    Pleaze research until you are absolutley certain before ever doing this!
    I disclaim any damage that may or will happen!
    news break! they can tell ya much better than me....
  9. Tedster

    Tedster Techspot old timer..... Posts: 6,002   +15

    one thing that occurred to me is that running more than one power supply would mean more than likely they would run in different phases. Bearing in mind that the output is DC, it might not matter much except in memory timings.
  10. SOcRatEs

    SOcRatEs TechSpot Paladin Topic Starter Posts: 966

    Dual not parrallel

    I agree, that's all I need is to get an out of phase dc spike :confused:

    I only run second psu for x-tra fans.
    And every thing is common grounded without mixing it up the out puts.
    So far no prob to report. whew :approve:
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