PC power supplies

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Some newer PC power supplies now have up to 4 separate 12V rails. The total
power is stated at up to 60 Amps at 12V total for an average 650W or 750W
PSU.

If I was to need a single 60Amp channel, would it be OK to connect all of
the separate 12V channels together?

Before you mention it, I understand the limitations of a PC power supply, in
that it needs a load to start properly, and needs a pretty good load on the
5V supply to regulate well.







Re: PC power supplies

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If  they are truely 4 seperate rails it's probably not the brightest idea to
just join them all together. 60A at 12V does seem like an awful lot and I
assume you are not going to be drawing large currents like that
continuously.  Is it possible to use a 12V battery and charging arrangment?
Does the 12V have to prescisely regulated?

Simple load sharing using resistors might work to an extent but it would get
a little warm :)

James




Re: PC power supplies

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About a year ago Elektor magazine in the UK published a project to convert a
PC PSU for low voltage halogen lighting, but it involved re-winding the
transformer and some changes to the PCB.



Re: PC power supplies
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Much simpler (and not a lot more expensive) to simply buy a purpose
designed unit:
http://cgi.ebay.com.au/1000W-12V-83A-Switching-Power-Supply-CCTV-DVR-Radio_W0QQitemZ360022982326QQihZ023QQcategoryZ20589QQcmdZViewItemQQ_trksidZp1742.m153.l1262
You get more grunt than you need, better air flow, and proper big
beefy terminals.

Dave.

Re: PC power supplies
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I suggest you read the label again, I think you will find the 12v output
limited to a much lower level current. I dont know the output current of
the 650 0r 750W, but I just looked at the figures for a 400 watt supply
12v output is limited to 17 Amps, it is the 5v and 3.3volt outputs that
have the higher current output 28 and 20 amps respectively.

                   Laurie




Re: PC power supplies

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total
750W
of


I could be wrong, but I believe four 15A rails is actually less per rail
than one 17A rail. Whether they can really manage 15A on all 4 rails at the
same time is another matter since that would be above the rating of a 650W
supply, not including any other voltage rails!
*Maybe* with a 750W supply. However you can't simply connect them together,
as the OP wants, in any case.

MrT.



Re: PC power supplies

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I think you may have it the wrong way around, are you use 60amp is 12V and
not the 5V. If you can actually draw 60amp at 12V the supply would have to
be at least 1200W once you add the 5V and 3.3V.



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