Make a computer power supply external

[baalek]

I have a small power supply in my computer and I noticed that its form factor is kind of the same as the one of laptop external power supply:


So I was thinking about removing it from the computer case to make it external as it's the case for laptops. That would allow for a smaller more easily cooled down case. But this raises two problems:
- as the power supply would be outside, I would need longer cables to be able to have it at a reasonable distance of the case
- currently the cables take a lot of space, in the case that's ok but if it's external it would be better to only have one somewhat thin cable
- I would need to be able to plug and unplug it easily as I want both to be separate items for easier transportation

To tackle the first two problems I was thinking about moving the PCB that you can see on top of the power supply inside the computer case and make my own (longer) cable based on the 12 currently soldered on the PCB. So that means unsolder those 12 cables to solder them on longer ones and combine them into one.

For the third, the only solution I see is to add a connector on the new cable I just mentioned and another one on the computer case.

I have very little knowledge in electronics, I just figured I could do that because it's basically just soldering things, but I'm probably overlooking many issues.
So my questions are:
- do you think that's feasible and if so, do you have any advice ? else why ?
- Is there some connector in particular I should pick ? Is there some things I should pay attention to regarding connectors ?
- out of the 12 cables soldered on the pcb, three are ground, I guess I could just use one that I will separate in three at the end right ? That will make the cable thinner.

 

[Harald Kapp]

to make it external as it's the case for laptops.

Those work differently: they deliver ~19 V DC to the laptop where all the required voltages are generated. The power supply you have delivers 5 different voltages directly to the mainboard.

do you think that's feasible and if so, do you have any advice ?

Feasible: yes.
Recommended: no.
You'll have up to 15 A on some of the wires. Peak current even more. The longer the wires, the higher the resistance and consequently the higher the voltage drop along the wire. Not only will the wire become warm, worse is that the voltage that reaches the mainboard may be substantially lower than the expected nominal value, e.g. 4.5 V instead of 5 V. This may negatively influence the stability of your PC. You could combat this by using thicker wire, but that will make the construction even more bulky.
For the same reason do NOT use a single ground wire. Use three wires as present in the design. This is noit only a recommendation, this is a must.
As for the connector: I would use the same type of PC mainboard connector as present on the power supply. It is a standard PC mainboard power connector.

Last not least there are questions of warranty and safety. This kind of power supply is designed to be used within anoterh case (your PC) and, as I can see no fan, is likely designed to be cooled by the airflow from the PC's fan(s). You will have to put it in an enclosure of its own, including a fan and openings for cooling.

Long story short: Without you knowing exactly what you do - don't do it.
Just my humble recommendation.