PCFormat Forum Archive

Recently I've been looking to upgrade my graphics card, but I had insufficient power. So I thought why not just add an extra 200watt PSU that was laying around instead of spending heaps of cash on a new one. My goal with this is that I can connect all my HDD's, CD-ROM's, fans and lights onto the 2nd 200w PSU, and only the motherboard and graphics card on my main 400w PSU. So now I'll be showing you how to use 2 power supplies on one computer

This is my how my case looks


And this is the 2nd 200w PSU that I will add


Disconnect everything, and I recommend that you take out your HDD as well.


Cut the green wire on the 2nd PSU. Don't worry, you don't have to guess James Bond style, because there is only one green wire


Also cut the black wire that is between the green and the blue wire.


Cut the same 2 wires on your main PSU


I will use this wire to link the 2 psu's together. How this works is if you hit the power button the motherboard connects the green wire to the black wire to turn on the PSU. Thus if the mobo turns on the first, the second one will also turn one. I marked two of the connected ends so I will not get confused. I call this the "link wire"


This is how I will connect the link wire to the main PSU


But before I do that, I will first connect the link wire to the 2nd PSU. (You see that the black marked ends will be connected to the black wire...)


And now to mod my main PSU as well... I don't really like the idea of having 2 power cables come out of my computer, so I will give the 2nd PSU power directly from the main PSU. Be very careful when opening a PSU, because the capacitors might still contain some charge. Wait a few minutes after you unplugged the psu, or wear some thick rubber gloves. Always better safe than sorry.


I will use this standard power cable,


and cut it in half.


Keep the part that you plug into the PSU, and strip the wires.


Now solder them on where the main PSU's plug is located. Now this will feed the main PSU and the 2nd one. Brown on the left side and Blue on the right. Sorry for the low res pic.


Now reroute the cable out with the others and close your main PSU.


This is where I will fit my 2nd PSU for the time being.


Now connect the link wire. DO NOT SCREW IT UP. You can make extra sure that the green wire will be connected the the green wire, and the black to the black wire...


Plug in the cable from the main PSU into your 2nd PSU.


Put back the HDD,


and plug everything back where it belong. (Logically you will use your 2nd PSU plugs as well...)


Put the case back on the table and plug everything in


Push the power button...


And VIOLA!




I enjoyed doing this mod, and I hope that if you find it usefull, it will serve you well... Oh and remember, on your own risk.

Regards,
TheModDoctor

cool guide.

Kwl man! a suggestion if I may... mount the 2nd psu at the top of ur case either in the 5.25 bays or just behind and vent the extractor fan out the top with a duct or out the side panel. Where it is at the moment ur gonna put a lot of heat in ur case

Nice idea tho , I might follow suit

ps. I just noticed you have an unused 80mm fan mount at the back, maybe try duct it out there, but dnt disrupt airflow to the cpu fan

Now if only you can fix Eskom there wont be problems

Mauritzvw1 wrote:Kwl man! a suggestion if I may... mount the 2nd psu at the top of ur case either in the 5.25 bays or just behind and vent the extractor fan out the top with a duct or out the side panel. Where it is at the moment ur gonna put a lot of heat in ur case

Nice idea tho , I might follow suit

ps. I just noticed you have an unused 80mm fan mount at the back, maybe try duct it out there, but dnt disrupt airflow to the cpu fan

thanx dude . Yeah I know I'm putting lots more unwanted heat straight into my case, so I'll really look for a better place to mount. Maybe like you said, through the open fan slot...

StarBound wrote:Now if only you can fix Eskom there wont be problems

BWAHAHA Yeah thats the plain truth

this....is eggzactly wot i needed....cant wait to get home .....thx dude.

Thanks man!
I really needed a guide like this!

Thanks.....sorted!

Really nice mod, very useful too. Thanks

Nice guide! Careful when you open PSUs. The capacitors can still retain charge and you can get shocked. Wear thick rubber soled shoes in case. The chance is quite minimal but rather safe than sorry.

I am glad you are trying to balance the power used by the 2 supply's. If you didn't you might have gotten a voltage difference between the two sets of black wires (The negatives). I would still suggest you connect the two sets of black wires more securely together (a nice thick wire between 200W and 400W negative lines). That way you can eliminate any voltage differences between your MoBo and say HDD for instance increasing the life expectancy of both...

Samaya wrote:I am glad you are trying to balance the power used by the 2 supply's. If you didn't you might have gotten a voltage difference between the two sets of black wires (The negatives). I would still suggest you connect the two sets of black wires more securely together (a nice thick wire between 200W and 400W negative lines). That way you can eliminate any voltage differences between your MoBo and say HDD for instance increasing the life expectancy of both...

QFT

Thanks! I'm glad you guys liked the guide.

Samaya wrote:I am glad you are trying to balance the power used by the 2 supply's. If you didn't you might have gotten a voltage difference between the two sets of black wires (The negatives). I would still suggest you connect the two sets of black wires more securely together (a nice thick wire between 200W and 400W negative lines). That way you can eliminate any voltage differences between your MoBo and say HDD for instance increasing the life expectancy of both...

Thanks, I will do that. What I did was connect the hdd, cd-rom, lights and fans to the 200w psu, so that my 400w can drive my mobo and new graphics card. I wanted to get the load off my 400w because I was unsure if it would have been enough, but now I've got no problem.

Hex Rated wrote:Nice guide! Careful when you open PSUs. The capacitors can still retain charge and you can get shocked. Wear thick rubber soled shoes in case. The chance is quite minimal but rather safe than sorry.

Truth to that. I'll edit the guide, because this is quite important. Thanks.

TheModDoctor wrote:

Hex Rated wrote:Nice guide! Careful when you open PSUs. The capacitors can still retain charge and you can get shocked. Wear thick rubber soled shoes in case. The chance is quite minimal but rather safe than sorry.

Truth to that. I'll edit the guide, because this is quite important. Thanks.

IMHO "thick rubber soled shoes in case" not gonna help you much(unless your barefoot on a very good ground like a metal floor...) and since a capacitor has both + AND - so if you were to touch the wrong pins and they were charge it would discharge through you regardless of your shoes... (LOL) so the SAFEST way is to get a (plastic handled) screwdriver or something and short out the pins of the big capacitors (ignor the small ones) and you will be good!