Introduction: How to Build a 24V Power Supply From 2 ATX PSU

Picture of How to Build a 24V Power Supply From 2 ATX PSU

Two ATX PSU = One juiced DIY 24 Volt DC Power Supply

Before we get going, i have to make it clear that this is by no means the safest solution, and that might even be and under estimation. I am no expert, and copying my steps is at your own cost. If you are in doubt don't try it.


This is my first instrucable since i couldn't find this project anywhere i thought i might aswell document it with pictures.
Also English is my 2nd language so bear with me.

Well, what you get when done is a 24 Direct Current (DC) Power Supply (PSU).

Parts list:

2* XXXX W ATX power supply.


A good length of mains cable.

Scrap wood or what you think is suitable.

Common tools (screw driver/hammer, saw, nails/screws and so forth)

Soldering iron with accessories or alot of male/female connectors.

Nice to have list:

A clue gun.

Multimeter. I nice to test things out before frying electronics.

Common sens.

Everything was sourced for free except for tools. This made this a perfect fit for my needs.


If i missed something please point it out, but if you have the above tools i have no doubt in my mind that you can make it.

Look all syncronyms and words up on wikipedia before asking.

Step 1: Theory / Build

Picture of Theory / Build

Since there more and more computers laying around the junkyard theres more and more ATX PSU to get for free.

The higher the wattage  described on the PSU the more amperes it can pull when done.
Small PSU will be suitable for testbeds where bigger could be used to weld or power a CNC (as I'm doing).

Before going any further if you scavanged your PSU like I you should test them out before spending more time with them.

Short PIN 14 (on standard ATX PSU) to any ground wire. It will make the PSU turn on, test with a multimeter. For any iregular PSU search around for howto-short-a-PSU. For pictures (i forgot to document that step) just take alook around instrucables and you'll be able to see how to do that step. Theres different way of doing this, but they all do the same job.

There also alot of chatter about how you keep the woltage steady without spikes. Again see other instrucables since most PSU are different an all have different build in features.

I went with a KISS solution.

The two PSU is now called PSU A and PSU B

Since theres some capacitors, inside the cabinet, which can still have a charge in them, wait a while before working with the PSU if they have been powered recently.

Now tear apart both of them. You do this to clear any ground connection there might be, remember to remove the ground (GND) from the mains line you are powering the units with, then you are sure that part of the project don't go FUBAR on you. I would not reuse the metal cabinets, period. Theres way the much risk in them making a contact with any loose wires. Which could result in frying you/electronics.

We can then procced to connect the +12 V wire from PSU A to PSU B GND wire, that will give PSU B GND a +12 V DC as GND then you add the additional +12 V DC it produces on it's own when powered on. To utillize the +24V DC you've created between the PSU you need to use PSU A GND wire  and PSU B +12V DC wire in operation and between those to wire to be more excact theres +24V DC @ the amperes that one would have given.

I also slashed all wires i wouldn't use for this project to inhance airflow in the small cabinet i build. Again think twice cut once.

Step 2: Leach the Beast

Picture of Leach the Beast

Create a box and make it just as safe as you treassure your own life.

Hint: I'm refering to the danger of electrocution.

When you are working with tree, in my case MDF, make sure you dismantle the PSU from the mockup board. Before cutting and clean all pieces very good. Just to minimise the risk of a fire turned on by any sparks.

Since all PSU are different i had to make seperate on/off switches to PWR them on. First i PWR PSU A then PSU B. Before i put switches in it only sporadickly PWR both on and only gave +12V DC out because PSU A didn't function properly.

Step 3: Enjoy the New Tool.

Picture of Enjoy the New Tool.


john5247 (author)2013-12-19

Hi Zilver. All very excellent! But you do too much!
You can leave PSU A complete in its own case. Only open PSU B to disconnect the case ground from the circuit board. This leaves the mains ground still working on the metal case. The two metal cases then still have a safety earth ground and can touch each other - or even be bolted together.
PSU A only needs a link between green and black to start it. PSU B needs an on-off switch. Now take about 8 black wires from PSU A to be your negative output for CNC
and about 8 yellow wires to the positive output for 24V CNC.
Then join 8 yellow wires from PSU A to 8 black wires on PSU B as you have done.
Some say that the thin red and thin orange "sense" wires should connect to their thicker red and orange supply wires. Some people also put 12V car bulbs on the 5V rail because some very old ATX need a load on 5V to regulate properly.
To be honest most newer ATX don't need anything.
My 24V ATX is wired all inside the 2 metal cases which are bolted together and all the external computer wiring loom is gone. I have one mains socket with on-off, one start button for PSU B and two 24V output terminals on 4mm banana sockets.
Yours is an excellent Indestructible - my only worry was to leave as many safety grounds on as possible and just "float" the black OV wiring of PSU B.
Considering that English is not your first language you make really good use of many English idioms ......

jjmcdsc (author)john52472017-11-24

If the power cord for ps1 was coupled with another and the ground was cut out on the second cord, you can power both units using the modified cord without having to open either of them up as long as they are isolated from each other and chassis don't touch you're good to go

Dinesh Kalsaria (author)john52472017-04-03


It was interesting reading your comment on 2 atx for 24v dc. I am trying to make one. Will yo be kind to provide me detailed wiring in form of a sketch diagram. I dot want to go wrong and make mistake. Your help will be useful

Bverysharp (author)john52472016-10-27

Hi John! I would like to ask you about putting a start wire switch in PSU B. I have wired up the PSU's with both start wires connected permanently to their relative earths, and as long as there is no significant load, PSU B almost always starts, but if there is any significant load (eg a stepper motor driver board) sometimes PSU B doesn't start. Would putting a switch in the start lead for PSU B fix this?

john5247 (author)Bverysharp2016-10-27

How are you switching the mains side? If you wire the mains to one switch so both supplies get power at the same time should help. Are the ATX boxes identical? If not try reversing boxes A and B. Finally you could get a double pole switch so the green - black link is switched for both boxes at once. DON'T MIX your blacks, the one from A is a real zero volts, but the black from B is at +12V from the A supply yellow. A double poe switch has two isolated electrical switches under one mechanical button.


Bverysharp (author)john52472016-10-30

Hi John! In the end I put a switch into the soft start of PSU(B) and bingo! No more problems.

john5247 (author)Bverysharp2016-10-30

Excellent! Now you can add supply number 3 and go for the whole 36volts .... or not. You should continue to collect a spare ATX as they come your way though. They don't live forever.


FadiR1 (author)john52472016-09-19

I'm very interested in this design but there is one problem that I
see with it: the parts of these psu were rated for a specific amount of
Watts. By putting the second one in series, I'd be doubling the voltage
and the overall wattage that's being loaded on it. These actually
expensive psus I'm working with and I can't afford to blow one up. How
does one go about verifying if the PSU can handle the doubled wattage?

john5247 (author)FadiR12016-09-21

Hi Fadi,
Your 2 power supplies can be seen as a pair of 12 volt batteries when the DC ground is isolated. If one battery is a large car battery and the other one is a smaller motorcyclel battery you can only draw the amount of energy out that the smaller battery can provide.

Even if you have 2 similar car batteries, one might be older or weaker than the other. The weaker battery will provide as much power as it can and no more. The extra capacity of the bigger battery (or PSU) counts for nothing when they are connected in series.

Don't forget your power supply provides the power and the load takes what it needs - the power supply can never push extra power into a load and damage it.

Please take care with the high voltage side of these power supples.
Electricity only kills you once.

true78 (author)john52472014-04-17

So John, are you saying you float both 12v dc case grounds and then just have the cases ground the110vac? The ac grounded cases can then still touch each other and the red and black 12 leads are just treated as standard 12v wiring such as those found on a car battery? I ask because I'd like to take two 12v 10a computer power supplies and use them to run an all in one gecko driver/controller. (g540 model) It will be running three 3.5a NEMA 23's. If I recall the gecko asks for 15-40v so I think this combination would be a good middle of the line match.

john5247 (author)true782014-04-17

Yes, find the circuit board screw that connects black negative to case ground and insulate underneath the PCB where the screw used to be. The screw will be near all the black, red, yellow output wires. Don't remove the screws at the other (high voltage end) of the circuit board.
Test the black wire to ground continuity with an ohm meter as you take the screw out so you can see the connection break as you do it. Check it again after you fit the insulation under the board.

Now you can stand the two ATX supplies next to each other - or even bolt them together and they will have a power safety ground.

The max you can get out of 2 ATX supplies is 2 x 12 volts. The 12 volts are on the yellow wires. Join yellow to black in the middle and tape it. (Like two car batteries) The other yellow and black across both supplies should give you 24 volts, but only 10 amps. You can add the volts up, but the max amperage is that of one supply.

Some guys on some older supplies swear by loading the 5 volt red wires with a small lightbulb. loading the 5 Volt wire can help the regulation of the whole supply (all the outputs). If you use a 12 volt car bulb like a stop light it will only glow on 5 volts. You may see a slight increase in your 24 volts if you do the lightbulb thing.

Also, some guys say that you can short black and green in one supply, but you might need a switch on the other one. As your load is potentially 10.5 Amps you might want to put switches on both green wire start circuits.

I know nothing about Gecko. You should check it's current at 24 volts if you can. They might be talking about drawing 3.5A at 15 volts.
A better indicator would be how many Watts it needs. Then you can work out the current at 24 volts.

Don't forget there are lots of Chinese switch mode supplies on ebay.
The ATX gig is only good if you have access to cheap or free ones.

good luck
Manchester UK

FadiR1 (author)john52472016-09-19

Yeas, but even though the amperage stays the same, the total wattage is doubled b/c voltage is doubled, if at some point down the line he halfes the voltage with a resistor, he'll have double the amperage.

brianfroelund (author)john52472014-08-15

Thanks for the detailed explanation. I ended up doing it exactly as you explained. However the powersupplies I found had negative to case going through two of the screws so had to isolate both of them. Just a heads up!

john5247 (author)brianfroelund2014-08-16

Were both screws near the end of the circuit board with all the red, yellow and orange wires leave the board?

The screws at the high voltage end of the board should stay in place as a saftey ground.

The circuit board has two completely independant "halves" The only link between them is magnetically in the transformer and optically in the opto-isolaters that carry the feedback signals.

Also try and leave the green ground wire from the mains power connector pin 3 attached to the metal case - that's the main safety ground.

good luck with all your doings


bluedragon776 (author)john52472014-07-28

Hi John5247 and Zilver

Question? Is there a way to use the additional dc power levels ie +5, +3.3? I ask cause I saw this

and thought it would be useful. If any thing it could supply power for the BOB or some other device. I'm also asking cause I'm wondering what the power would be if I where to float the 5v and 3.3v. Would it double?

john5247 (author)bluedragon7762014-07-29

Yes. with the Dc negative black wire floated (disconnected) from the metal case and mains power ground you can get a range of voltages from the two ATX supplies.

Assuming the yellow 12 volt output of the first supply is connected to the black negative of the second supply, you can now get the following voltages. 3.3, 5, 12 as usual from the first supply. Then 15.3, 17 and 24 volts. THERE IS ONLY ONE REAL NEGATIVE NOW. The black wire of the second supply is at +12 volts from the first supply.

The original plan to give 24 volts from 2 supplies can be modified further. Instead of using 12v yellow to black negstive on 2nd supply, you could use + 5volts Red from 1st supply to black on supply 2. Now you can have 8.3, 10 and 15 volts. You cabn still use +12V yellow on supply one, but you lose the 24 volts.

Finally you could use oragnge +3.3V connected to black on PSU 2 and get 6.6, 8.3 again, and 15.3 Volts.

The easiest way to do this is to make black, orange , red and yellow connectors for each supply. Just remenber black from PSU one is your only negative. The black from PSU 2 should be clearly labelled as your voltage selector wire back to PSU one.

These supplies are really clever and well protected. Any mistake or short and the supply will shut down. Reset just means turning off and on again.

bluedragon776 (author)john52472014-07-29

Ok you said I will lose 24vdc so there is no way to have all said dc volts and 24.

I was thinking there would be 7 maybe 8 voltage ranges including the 24. The reason i asked cause the BOB wants +5 and -5 to the rail the has the relay for the spindle and limit switchs, but then I need 24 thou 12 would work but wouldn't be as strong of course to power the drivers to steppers. While the BOB has a USB port for power I don't want to be tied to it and the PC. The BOB also has a manual controller/gcode recorder so I don't need a PC if I wanted to run the CNC manually.

I just thought if I ran a red +5 and white -5 from PSU 1/A to BOB that would power it. I'd start wiring and testing but I need a couple switches. Don't really need the other volts but it could be useful maybe.

This if my first CNC and has taken some time to build by hand and save for the electronics. But it has taken this long and I'd rather take my time and get things right.

Thx for your advise and everyone's else as well.

john5247 (author)bluedragon7762014-07-30

Yes you can use PSU one black and red for +5V, then black and white -5V for the BOB - just check the current drawn by the BOB. Then as before PSU one yellow goes to PSU two black and you will get +24 volts at PSU two yellow.

Let's make this really clear for any TL:DR guys out there reading this.

Open up two ATX power supplies. Isolate the black zero volts wiring from the metal case by removing a PCB screw. Link the green "power on" wire to an 0 volts black to switch the supplies on seperately. Mark the black from PSU 2 with pvc tape to distinguish it from the real black zero volts. THE TAPE MARKED BLACK IS NOT ZERO VOLTS anymore - it is the link wire to get higher volts out of PSU two.

Now every voltage on all the coloured wires from both PSUs are available, but beware that some are quite low current. They all reference to black zero volts on PSU one - even the -12 and -5V outputs.

Good luck with all your doings

bluedragon776 (author)john52472014-07-29

Oh one other thing. The black ground from PSU1 and the yellow from PSU2, do they have to be bundled together or are they essentially 24vdc each, so if I have 6black and 6yellow I could run 1n1 to one of the driver boards and so on then have a couple free 24v leads hanging there?

I wonder cause if I bundle them I then have to run them to a distribution block or just run a pigtail from one board to the other. Maybe a heavier guage wire thou it can't be to much heavier.

john5247 (author)bluedragon7762014-07-30

Yes - you can use the original PSU wiring for distribution just like the PC does. All the yellows form one PSU are internally connected. Only some expensive high end supplies have "dual rail" outputs where the 12V and 5V rails have two independant outputs isolated for motherboard and graphics.

true78 (author)john52472014-04-17

Ok, so I got a pile of these two IBM think station power supplies for free, the whole computers, they are 200w max. I may have already shaved off too many contacts on the first one I opened up, as it had three grounded screw mount tabs in total inside the power box, I'll have to open it up and have another look at it. The blacks are all non grounded to the case now, and the middle plug-in tab is still grounded to the case What I did was take a chisel and shave the contact off down to the bare board about a cm around the mounting post so no conductor was left, I then added a 15mm plastic washer in between just to make sure nothing would touch if it were to shift after being dropped or something. My biggest question are: maybe repetitive....

1. If I float each 12v dc board in both supplies can I leave *both* the 115v ac boxes grounded with their original cords and still allow them to touch.

2. To protect against any ac/dc short making its way out of the power supply case through one of the 12vdc wires, could an inline 10a fuse be put in the inside of the case. My thought is anything shorting inside to the wall of the case will ground out on the 115ac cord ground, but in the event that a wire contact broke free and hit a 12vdc output feed it would at least pop the fuse before exceeding 10a.

3. The 3 steppers are 3.5a max each, and for the size of table top cnc engraver I'm playing with it would be unlikely they will ever be maxed out. I'm not 100% sure if they spike on start up or not, but if not could I wire both in parallel to the same switch? I was thinking of using the original PC switch and cabinet to house both power supplies. I just like this switch because it has an led indicator built in.

4. each unit has 4 yellows and 11 blacks. Tie the 4 yellows from "A" to the 11 blacks from "B", the remaining 11 blacks from "A" and 4 yellows from "B" will become my 12v battery posts?

Just want to check if we're on the same page.

Thanks for the info.

john5247 (author)true782014-04-18

Hi True - Like I said to the OP Zilver who did the instructable, don't do too much. Take the lid off, put a meter from black to metal box. Remove one screw near the black wires. Lift the board slightly and watch the meter as the circuit breaks. Slide a bit of card or tape under the board to keep the track off the old mounting post.

Cut every wire short close to the circuit board. Leave the green, six blacks, four yellows and one red as long wires. Tape or hot glue the cut ends of all the other red, orange wires. Put the lid back on.

Label one supply A and the other one B. Label the yellow wire bundle of A with black tape and four of the black wires from B with Yellow tape (or whatever you have). Join the tape marked blacks and yellows together, tape over and push out of the way.

Each supply needs its green wire shorted to a black wire to start the supply. You need a switch like a toggle that stays on. The lovely illuminated push button switch is a momentary action type and is no good - sorry. You can probably still make it's LED light up though as an indicator.

The supplies can both go in the same tin box. Both AC cords can be grounded. Go ahead and add fuses, they never do any harm!

And finally, just for info. If you turn over the PCB from one of your trashed supplies you can see the board is split completely in half electrically. All Switch Mode supplies (SMPS) are like this. The high voltage AC side is chopped up at high frequency. It gets to the DC side by magnetic coupling in the transformer. The trafo is given a breakdown voltage protection in kilovolts. 115 VAC isn't crossing this gap! To control the AC power side with whats going on loadwise on the DC side, there is an opto-coupler (an LED and a photo transistor in a chip) This also has a very high breakdown voltage. 12 volts is not going to connect to the AC side, ever.

The only wire from DC side back to AC side is the ground on the circuit board which we have just disconnected by unscrewing and insulating it.

If an AC fault develops and puts 115V on to the case. The ground will catch it and the fuse will blow. If a DC fault develops and 12 volts touches the metal case .... no one cares, no one is going to die so the government and ATX don't regulate or make rules about it.

true78 (author)john52472014-04-18

Ok, so I need to unground the 12v dc on one unit only, while maintaining the factory ac cords and ground connections. That does simplify things a lot.

Do you know if the computer power supplies are being switched on from the dc side, or are these 12v switches connecting to a relay that is causing the 115v ac to power up and feed the 12v dc?

Thanks for the time.

john5247 (author)true782014-04-18

"switching on" doesn't really apply to an ATX SMPS. Some supplies have a mains power switch, but many don't (same with 110 - 220 volt changers).

The supply is a complex set of safety circuits. You can "start" the supply by grounding the green wire. If you short circuit any output the supply will "shut down". This is not the same as "switching off".

Think of it like the signal from your battery operated TV remote. The TV is never truly "off", it is just asleep. Off means "unplugged", "disconnected".

It means the PC or the TV remote is no longer in control of the supply.

For info - one of the many supplies inside your ATX box that makes 12, 5 and 3.3 volts for the PC, is a tiny supply that is always on. It is this circuit that responds to the green wire being grounded. It also works the "power good" circuit that keeps the supply from shutting down.

true78 (author)true782014-04-17

I should clarify #3 I meant run the green/black start circuits in parallel from one switch. The power supplies I will still be running in series.

true78 (author)true782014-04-17

As I suspected, I had removed more grounds then I should have, I removed the one for the 12vdc board and had removed the two on the board with the 115v side with the cap. So that supply unit is getting tossed and another one from the pile will be getting just the single 12vdc side isolated. John, you must have done a few of these units before? Good info.

john5247 (author)true782014-04-18

Yes, the high voltage AC side of the circuit board should remain firmly grounded to the case for safety. Otherwise we could just cut the ground wire from the power socket to the metal tag. This would float the DC side to allow series connection to a second or third supply, just like batteries, but the safety ground would be gone. This might cause death and is probably illegal in 57 states.

Incidentally, once the 115VAC has been rectified inside the box it rises to 165V DC. In the UK the 240VAC power rectifies to 340 V DC!!. This is why it is in a grounded steel box and has no vent holes big enough to get your finger in. ATX spec turns a PC into a safe 12volt max system.

and finally, just in case. Laptop PSU's are 19volts so they have extra to charge the batteries and run the laptop at the same time. You can't charge a 12 volt battery with only 12 volts, the charger has to be stronger than the battery .....

john5247 (author)true782014-04-18

You need a double pole switch where each green - black pair is a seperate circuit. You can't parallel them. Each green is independent. Also, don't forget that the A supply black wire and B supply black wire are no longer the same voltage!

B supply black wire is now running at 12 volts due to its connection to the yellow wire from the A supply .....

By the way, in my previous mail I suggested bringing a long red and black wire pair out of the box. This is to add individual dummy lightbulb loads to improve the voltage stability of the PSU. You could also use the 5 volts with a resistor for your LED indicator. You might find the bulbs aren't needed, but it's a pain to get a red wire out of the box later if you find you need it. If you don't use it just tape the end up.

Zilver (author)john52472014-11-21

Hi John.

I know i did, but i had no use for the cabinets, and wanted to be on the safe side, since the PSU had screws to ground i wanted to circumvent it completely, and show others the same method.

Sure you can do it KISS, and if i need 24V for another project with different PSU i might do it. but these PSU arent' bolt on friendly in the first place.

Nice short guide you wrote i liked it, i still see some are confused, and for those i would recommend doing like i did.

Pxista (author)john52472014-03-31

can you please detail your project ?? is exacly i need...

john5247 (author)Pxista2014-03-31

Hi Pxista,

All we are doing is disconnecting the black wires on the ATX PSU off the metal case. Take off the case lid - with the power off of course! Look at where all the DC output wires are coming out of the circuit board. All the black wires are connected to the metal case of the power supply. The connection is made with one of the screws that hold the circuit board down.

If you connect your test meter to the metal case and the black wires it will beep or indicate a short circuit. Loosen one corner screw and move the circuit board up a little - away from the case. The connection between the black wires and ground should be gone.

The screw to remove is always on one of the corners near all the red, yellow and black output wires. DO NOT remove the screws from the mains power end of the PCB. The screw you take out has to stay out. You also need to slip some insulation under the PCB in the corner where the screw used to be to prevent the metal touching again.

What you have now is a "floating DC ground" on the power supply, which means it can be connected to a second supply in series to increase the voltage. IT WILL NOT increase the current. That will still be the maximum available from the smallest of the two supplies.

The mains power safety ground is still on the metal case for your safety. Switch mode power supplies use two completely electrically seperated circuits on one circuit board. The two parts talk to each other through a transformer and opto-isolators. So the utility power is magnetically and optically isolated from the low voltage DC part of the supply.

There is no real need for a DC power supply to have a ground connection. Most HiFi and audio equipment is built that way to keep ground currents out of the audio. The utility company safety ground is there to stop power that might turn up on the metal case if a wire falls off inside . If you look at a lab bench power supply you will see that grounding the DC negative is an option on the front panel. The same goes for oscilloscopes and other test equipment.

Pxista (author)john52472014-04-01

thank you dude!! i did it and worked fine.. now i will put the cases together and organize the wires and stuff.. Many thanks !!!

Zilver (author)john52472013-12-20

Hey john5247, thanks for the kind words and constructive criticism, i really appreciate it. If i re do the instructable, which i very well might, since i'd like for a cleaner setup, much like yours. I that case I'll properly end up reusing you ideas, i remember when i did this mod, i just wanted to be sure not to short anything from PSU B, think I'll do a delayed start for PSU B aswell controlled by PSU A, but more on that if i ever get to it :).

Thanks anyways, and happy holidays!

Ahmed desuza (author)2017-11-24

I am sorry for this question, but the second atx had never start working even when I short the green black wire, I asume the black wire have 12 volts from the first atx did it work like that or nah, in detail please

gullfunk (author)2011-06-07

you can get 24v from one psu you use the -12v(blue) wire as ground and a +12v(yellow) wire as positive. and you get roughly 24v

Lima79 (author)gullfunk2016-11-24

bro its not a good idea if the device is a single 12v:0v then the SMPS
will short circuit and even damage the SMPS or the device but works 100%
on a 12_0_12/center tapped device because the black wire is always
needed, +12vdc/yellow-wire, black-wire/GND, -12vdc/Blue-wire this is a
center tapped and +12v/yellow-wire, black-wire/GND this is a single
12v:0vdc(the -12vdc blue-wire is useless with a single 12v:0v device)
must make the connection according to the device.

Zilver (author)gullfunk2011-06-08

Yeah @ 0.5 amp and thats not so useful for any applications of mine.

ArminĆ (author)2016-04-07

Why do you need 2 PSU when you can use only one. Just use +12V and -12V on P1 connector.

Lima79 (author)ArminĆ2016-10-31

Thank you, yep there is +12V and -12V, we might be able to use just like a 12-0-12VDC transformer but i am not sure to test it:) since i am new to electronics.

Lima79 (author)Lima792016-11-24

OK can't use a SMPS +12v and -12v on a single 12v:0v device, the device
must be a 12_0_12 or higher VDC it depends on the device or else
the SMPS will short circuit and shut down for few seconds.

OmnivoreNZ (author)2012-02-10

This site has a similar idea, stacking 6 PSUs to get 30V at 40A.  - but it looks much messier than the way you've done it. I hadn't thought of simply throwing away the metal cases which allows a much cleaner and better looking unit. Thanks!

Lima79 (author)OmnivoreNZ2016-10-31

"6 PSUs" so this can be done, i am not sure but if i ever tried connecting my 4 PSUs in series successfully, i will share out here. Thank you.

dreiseratops (author)OmnivoreNZ2012-09-15

This is beautiful!!!

Bverysharp made it! (author)2016-10-30

Hi Zilver. Thanks for your instructable on this. I was encouraged
enough to build one of my own, taking into account some of the comments
by other members. I left the power supplies in their cases, but
jumpered the 240V over from one to the other so that I only had 1 input
plug. I found that I had to put a switch in the soft start line of
PSU(B) to make it work reliably, but other than that, it's great! If
you are wondering why the box is so big, it's because I have put my CNC
control board & relays in there as well.

Lima79 (author)2016-10-29

Very nice tutorial BTW can i connect four 450 watt SMPS, this may sound crazy but i need a 45_0_45 @7-10amp SMPS or Transformer, i have searched everywhere on e-com sites even searched for a copper coil to build a Transformer myself but unfortunately its not available anywhere out here in Indian e-com sites, this is the reason why i need to connect four SMPS in series. Thank you.

just4flight (author)2014-01-18

Hi, does anyone know if I can use 3 power supplies to make a 36 volt charger capable or charging a 18v NiCd battery from a cordless drill? Thanks.

DakuluD (author)just4flight2016-02-05

yup 3 psu for 36v .Remove earth conection on PSU B and PSU C.Change PSU C 12v rail caps from any 16v - 25v to 50V (2200mF) for example

AndyW27 (author)2015-10-20

Hi Zilver, Where did you connect the green wire PSU B? As I know, Ground on PSU B is not ground anymore since you connected with positive from PSU A


MegaDAS (author)2015-05-30

pictures aren't clear at all :p

notzippy (author)2015-04-21

Another quick point if you choose to keep metal cases some boards have ground points built onto the cct board screw terminals. Unscrew the cct board from the metal case and isolate that portion of the board from the chassis (I used some plastic and adhered it to were the screw would make contact). Then re-attach the board to the chassis, (don't use the screw terminals you protected though).

About This Instructable




Bio: Working on a 40W laser, repraps, and IoT
More by Zilver:DIY 40W CNC Laser cutter, from bad to better with 3D printingProjector, 100W LED, watercooling, fan + Misc reworkHow to build a 24V Power Supply from 2 ATX PSU
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