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Combine multiple molex's from PC power supply for higher current capacity?

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racefan56

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I've been working on how to mount the internal parts of a PS3 (the "fat" one) into an old computer case to hopefully help keep it cooler, and because I want something to screw around with. I believe I've covered my bases on every issue of doing this besides the most major one, power. While the PS3 does have a power supply of its own naturally, I don't trust its reliability nor does it help keep things cool by laying directly on top of the PS3 motherboard in one big old ball of heat. What’s my solution? Drop the PS3 power supply and use a computer ATX power supply instead.

Though it'd be nice for the story to end there, it doesn't. Besides the issues of wiring the ATX power supply to attach to the PS3's connection points we also have the issue I've came here for, the issue of current. The PS3's original PS (power supply) is rated for an output of 23.5A at 12V. While I know I need an ATX PS that has a current rating of 23.5A or higher on its 12V rail for this to work, from my research the wires used for the 12v molex connectors in an ATX PS aren't rated to carry that much current (only around 11A each according to wikipedia [I know, shoot me]).

My proposed solution to this is to take 3 molex 12v lines from the ATX PS and run them together in parallel down to one single point to reach a new current capacity of the molex wires as a whole of around 33A (if the 11A rating I found is accurate). My question to you is, is that logical? Would that work, by one, reaching or exceeding the current requirement of the PS3, and two, satisfying that current requirement safely?

This all may sound entirely insane, and maybe it is, but I'd least like to know I tried to make it work. If all else fails I’ll just use the PS3’s PS or scrap the project entirely.


EDIT: Added a schematic of sorts to show how it may look.
 
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Hi.

Techniclally, there is no reason why yo can't do just that.

But be aware of this things:
* Make sure that each wire group (to each molex) has equal length to the other output wires. If one wire group is shorter, it will carry a higher load than the other wires and possibillity for overload is present.
* Make sure that all connections comes from the same output rail inside the psu. You might have to open the case in order to find it out. Be carefull as the capasitors might not be discharged.
 
You may also find this link useful as well as educational. The link in many places actually gets down to the actual connectors by manufacturer's part numbers and the current capacity by circuit.

Ron
 
The connectors are probably only good for 5-7A per pin so use all of them. Obviously, if the connector rating is lower than the wire rating, it makes sense to use two or more on each chained cable.
 
Hi.

Techniclally, there is no reason why yo can't do just that.

But be aware of this things:
* Make sure that each wire group (to each molex) has equal length to the other output wires. If one wire group is shorter, it will carry a higher load than the other wires and possibillity for overload is present.
* Make sure that all connections comes from the same output rail inside the psu. You might have to open the case in order to find it out. Be carefull as the capasitors might not be discharged.

Thanks for the tips :). I've read somewhere that even if a power supply is said to have multiple 12v rails they are actually just extensions of a single rail rather than all on their own. This could just be a wild conspiracy someone posted, but either way I'll make sure they're on the same rail.

You may also find this link useful as well as educational. The link in many places actually gets down to the actual connectors by manufacturer's part numbers and the current capacity by circuit.

Ron

Thats a very helpful link, thanks for sharing it. Looks like I'll need to combine more like 5 12v molex lines instead of the 3 to get the current capacity I need. Looks like wikipedia isn't the greatest source of knowledge on some things after all lol.





I feel much more confident in this idea now.
 
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Think about fuses too! :)

Ron
 
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