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Dual PSU How-Tos

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I understand that it's really simple to power the system with one primary PSU and have another one turn on in sync to power fans and whatever you might want to power off a second PSU.

But I'm still uncertan about 2 questions...

1. Can I connect say 2x +12V to + and one GND to - to get +V12 and dubble the amp (and thereby dubble the wattage) assuming that both PSUs have the same output.

2. Can I connect +12V to + and -12V to - to get 24V?

Hope these aren't stupid questions that I should have found the answers to :)
 
Re your first question Finken,
Yes you can do combine two rails of the same voltage from two seperate PSU's to double the amperage. Look at the Procooling article in the first post for the specifics. The nomenclature IIRC is Parallel (if you want double the amps) or Series (if you want double the voltage).
 
Ah ok, thanks a lot

Edit: Yes, there it is! :)
Didn't read it because it was about ATs :(

Thanks :)
 
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Now I know how to power a pelt with 2 or more PSUs.
But now I have a 3rd question I want to be sure about...

I can use 3,3 and 5 from each supply in parallel to power the rest of the system right?

Just want to make sure that it's not going to damage my MB and stuff because of to much power or something...
 
Finken said:
I can use 3,3 and 5 from each supply in parallel to power the rest of the system right?

Just want to make sure that it's not going to damage my MB and stuff because of to much power or something...

I would assume that the same procedure that you would use to combine the 12v rail would work on the 5v and 3.3v rails as well.
Although you don't hear much about weak 3.3v lines causing instabilities.
 
Quasi cross-post

What would be, in y'alls experience, a good PS to buy for a second PS? Given that Fortrons and Sparkles are up there, as are Antecs, would I be in decent shape grabbing up a Sparkle FSP250-60ATV for $19 or a Fortron ATX300GU for $22 as a second PSU for my system?

I want something to power my HD rack and some fans, and I figure it's almost as easy, and definitely cheaper, to add a second PSU as it is to drop the cash on a 480 or 550. The SL350 that came with my case is probably at it's limit.
 
Normally, I wouldn't be inclined to say "Go buy another PSU just for a dual rig", but if you feel the need, go with as cheap a good-quality PSU you can find.
 
Hey,

I have managed to get my second psu to power up. I did this by using the jumper wire and daisy chaining it to the power out (for a monitor) on the back of my internal psu.

I intend to use this second PSU (300w) to power an 80watt Tec and my 9800 (if it will take both). However the 12volt rail isnt giving out anywhere near what it should.

I've read conflicting advice about puttin a 1amp load on the 5volt rail to give the 12volt rail all its juice.

How have people gotten past this, whats the method for making a dummy/fake 5volt load ?

Cheers in advance.

Ecks

PS I am unwilling to modify my internal PSU, I want this second psu to run on its own - if thats possible.

Cheers
 
Just an FYI:
PCMods has ATX extension cables for $2.59 with free (domestic US) shipping.

Kinda makes the Burning Issues mod downright cheap and easy!

Edit to add:
That is, buy a pair of cables, cut down one and splice it into the other, then plug them into the original PS cables, leaving the originals untouched/undamaged.
 
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thinksnow said:
Just an FYI:
PCMods has ATX extension cables for $2.59 with free (domestic US) shipping.

Kinda makes the Burning Issues mod downright cheap and easy!

Edit to add:
That is, buy a pair of cables, cut down one and splice it into the other, then plug them into the original PS cables, leaving the originals untouched/undamaged.


what would be a correct way of splicing them into eachother? anyone knows the procedure?
 
thanks stool :)

has anyone here done it? any pointers?

i am more interested in paralel linking;

also, what's the deal with a resistor on +5v rail? any experiences?
 
mcoleg said:
thanks stool :)

has anyone here done it? any pointers?

i am more interested in paralel linking;

also, what's the deal with a resistor on +5v rail? any experiences?

I am about to do a dual psu setup in the next day or so. I have ordered the resistors etc and will take pictures and explain what I have done. The guides on the first post do a very good job, you should check those out. I am going to solder a jumper wire on the atx cable to make it start up when its plugged in. I will also be putting a dummy load on the 5volt rail in the form of a 2ohm 20 watt resistor (so I've been advised - will be experimenting) to stablise the 12 volt rail. I plan on powering a 80 watt TEC and if possible my 9800 from the same psu. That way if it fails both the tec and the 9800 are turned off saving them both !

Anyhows the resistors should be here today/tomorrow. Will post asap.

It seems very simple - the 5 volt load being the only problem.

Ecks
 
Thanks Ecks :)

i've got a couple of 200W rack-mount atx psu's i'll be experementing with. if they work, i'll use one of them to support my 330TP; basically i'd need to reinforce +5, +12 and m/b +3.3 lines that are sagging. well, at least that's the idea; i am not very handy, to tell you the truth.
 
Ok I am having some problems and need to go back to the drawing board. I have the PSU powering up but I cannot get a stable voltage on the 12volt rail - it reads about 11volts and jumps about lots. I soldered on a 20 watt 2 ohm resistor as advised in other forums and that provided to much power on the 12 volt rail (13+ and wouldnt have lasted).

I am far from a Electrical Engineer, just a post grad willing to experiment. I need some help, what resistor should I be placing on the 5 volt rail to sort out the 12 volt rail ?

Cheers

Ecks
 
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