(Adjustable) Power Supply 650 Watts 54 Amps for Under $50

The idea is to make a relatively small, compact power supply that can fit many purposes. This build will include the following ports:

• USB charger
• Car Cigarette socket
• XT-60 (RC)
• T-plug (RC)
• Banana plugs

It also includes an adjustable part that could be used for:

• Testing electronics
• Powering your laptop

This instead of only one pair banana plugs. I think it's also important that it can be built with a limited budget and that everyone can make this or a similar project.

Step 1: Making a 3D Model of the Enclosure

Be creative!

My advice: Make sure that everthing fits correctly. Take some time to ensure it fits perfect, rather than you manually having to adjust the enclosure with a saw, drill or file. This will take up a lot more time and the finish of the final product will not be as high as supposed.

I added my Solidworks files.

"Solidworks2014-Power supply .zip" see files

Step 2: Laser Cut the Enclosure

Convert the 3D model to 2D parts and laser cut them.

It cost me $8 to laser all the parts (wood and professional help included).

I added my DXF files (if you want to make the exactly same project).

Step 3: Prepare the Housing

First I sanded all the parts with a grinder. Then I glued them together and let them dry for 24 hours under the pressure of clamps. Then I again sanded the enclosure, and applied laquer to the wood. I waited for 4 hours, sanded the enclosure again, applied laquer and waited another 4 hours. If a better finish is desired, the last step of sanding, applying laquer and waiting can be repeated.

Step 4: Prepare the Power Supply

I disassembled this power supply from an old server. The specifications listed that it operates on 12 volts @ 54.4 amps. I salvaged the connector form the motherboard.

I searched Google for the serial number to find the start button wires of the power supply (the black and yellow wires in the pictures). When the black and yellow wire are connected the power supply will power on. It's like a usual computer power supply, where you connect the green with the black wire to get 12v, 5v and 3.3v.

I used 2x 6 mm^2 wire (9AWG) for the power distribution. Then I soldered an additional black and red wire for the adjustable part of the power supply.

Step 5: Adjustable Power Supply 80watt Max 130 Watt Peak

I looked at the datasheet of the volt/amp meter how to connect it. Then I extended the potentiometers so I could mount them in the enclosure.

NOTE: The potentiometer I used aren`t correct. Those are 10 step 10 kiloohm potentiometers. So I used the old ones for now but I ordered new.

**** i added the "electrical schematic" and "order list" ********

Step 6: Inserting the Electronics and Soldering

I used a simple step-down converter for the fan (12 to 6 volts) and connected it to the power supply and the fan. Then I inserted the electronics, ports and power button in the enclosure and soldered it all to the power supply.

Step 7: Testing

It is smart to first use a multimeter to measure the polarities and voltagea of every connector. You could, for example, put some load om every connector and make sure it works. Also some vibrations could be made to test for loose wires.

Step 8: Final Product

Some improvements that could be made:

• Order the correct potentiometers
• Order two of the same volt/amp meters (same display colors)

I now hope to inspire you to also make an (adjustable) power supply or a similar project. If you have any questions, please leave it in the comment or send me a message and I'll try to answer them for you.

Comments

[AlbertoF43]

Hi! Have you changed the potentiometers? Could you please give me a link for the model to choose for that board? Thank you very much (and sorry for my english...)!

[UNSEPARABLE TECHSCIENTIFICS]

COOL BUT SCHEMATIC WOULD BE NICE AT ALL!!!!

GREAT JOB!!!

A+

[Nick5678]

Thank you!

I made already a block diagram, do you want a upgrade of the diagram? With more details?

[ZOUDIO]

Nice job on the lasercut!

[kamhagh]

Nice! I made my own in a tissue box.... yeah....

I sadly couldn't find any multi turn pot in my country and had to use normal ones. it's a huge pain to use.... 0_0 but it still works! I used an ltc3780 and a 12v 10A PSU . it costed like 25$~. I already had the psu so I just purchased a ltc3780 and connected pots. it's nothing special to be honest. the main part is the step up and down module which is already available ^_^ Idiot me burned a LTC3780 board in the process so I had to order another.... don't use a metal screwdriver to set the value :|

[rbeforee]

Tissue box!! Wow? It's not a fire hazard? Or is it just proof of concept?

[Nick5678]

Paper will burst out at a temp op 200 degrees celsius, wood 250.

I hope my/your electronics don`t get this hot!

[kamhagh]

Lol I doubt it :D

[kamhagh]

You only live once xD I doubt anything's gonna happen! I don't have a printer or wood or metal or anything. Specially patience :)

[rbeforee]

I recently gained access to a laser engraver and a large CNC router. I've not yet used them, but I'm pretty excited. The router is for wood, not metal as I understand it. The laser is also not for cutting/engraving metal.

I was thinking about making an acrylic box for this project. The laser makes such beautiful edges, and the "adhesive" is pretty awesome. True joins. I with have to think of a fun pattern for the vents. Oh, and a way to create a hinged top for repairs.

[kamhagh]

Ps my op amp in the LTC3780 gets very very hot. and my Current is very off. my voltage is pretty accurate though. anyone has any ideas ;c?

[MaverickPT]

Hey, what is the model of that 5V usb charger? And is it connected to the LTC or the 12V power supply? I'm really interested in making something like this so i would like to know the parts ahha.

What i'll probably do is to extend the depth of the box and place a better heatshink on the LTC. Anyway, your project looks great!

[Nick5678]

The 12V is connected to the LTC and the USB charger is a separate unit that converts 12v to the 5v.

I bought it on eBay http://www.ebay.com/itm/311783941370?_trksid=p2057...

The order list, and electrical schematic has also been added to step 5, for more information.

I didn’t have the
time to fully test the adjustable power supply, however I used spacers so the
airflow can pass nicely, if it is necessary i wil increase my heat sink.

[kmpres]

Very nicely done! Unless I missed it somewhere, I might suggest you cut ventilation holes in the right side of your case so you get some cross ventilation. Your fan will work better and your server power supply will love the fresh air.

[Nick5678]

I have a small stroke in the back for my adjustable power supply. And don`t forget the very small black lines on the front (these are open). But it`s a good idea!

[rbeforee]

I'm still a n00b with electronics and have fantasies of creating some small scale solar projects. I really appreciate your Instructable. I need to tinker with electronics and more comfortable.

Forgive my incredibly ignorant question: other than the joys and benefits of DIY creations, is this like a snazzy power "strip" with more types of output ports? Are you using it as a versatile desktop "power bar"?

At first glance my mind said "yike! A wood box for power!?" Is the active cooling the reason this is safe to not catch fire? Or does it just by nature not get hot enough to threaten combustion?

Forgive me if these questions are already in the Instructable. Because of my lack of experience with power my eyes kind of glazed over for the measurement values. I could have missed stuff by not being experienced enough to understand the entire content.

I've very excited about this project, even though it is over my head. I know a few patient friends who might be willing to explain the finer details.

I am hoping to learn enough about electronics to build a solar-powered unit for Burning Man. I love the notion of not having to connect adapters to standard three-prong outlets. This seems cool for a cleaner appearance with each item having the correct socket.

Thanks for creating this Instructable. You've made in less intimidating and thankfully budget-friendly. Even though I have fewer random parts lying about, I have a tendency to not send dead equipment to e-recycling. I just need to learn what parts I can yank to give them a new life.

[bobbg53]

Radioshack used to make a 250 400 1000-one project kits that taught you a lot about electronics components, search e-bay for older used kits wile they might have basic microprocessors and large components compared to modern electronics it ll help teach you the basics.

But you can also buy Adreno kits and other stuff like this. These are geared more to programing and electronics, and a lot more modern.

I'm sure if you look around you will find kits like that to learn some basics on.

Most of its done using small batteries so no chance of electrocution.

Don't open the back of an old picture tube type TV it has a high voltage flyback that will kill you if you mess with it even if its unplugged.

You can take a 650 watt computer power supply and change it to a variable output power supply, or use an old PC case to house your project in. They are a dime a doz. you just need to cut out the holes for components. and isolate the case from the back of your power control boards. Most computer cases use stand off's for this. e/waste is a good place to find free componets.

[rbeforee]

Thanks bobbg53 !! I'm sad that they no longer make Heath Kits. I remember when I was little my father built a stereo receiver. Every once in a great while I'll see one for sale, but they are not economical anymore.

I've been warned about the deadly tv's. I love dismantling things, but I have a healthy respect/fear of those. The nothing that unplugging it doesn't make it safe freaks me out a bit, and makes me read up before thinking about cracking power cases.

I wish the kid-friendly electronics kits weren't so dang expensive. Learning the guts separately from improving my soldering skills would be handy. It would remove one potential point of failure.

I recently learned how to solder together EL wire and plan to design some lighting for Burning Man. One reason I'd like to learn how to setup solar juice. Batteries are not terribly problematic but I'd like to reduce my wastefulness in keeping in the spirit of the event.

Thanks for the guidance. It will help a lot.

[RubenFerol]

I am working at a power supply under 30$, and chose the same multimeter(around 3$):

The Amp meter is very accurate between 0.06 - 20Amps, but voltmeter not so sensitive in matter of tens of mV under 10V; with 20mV max error.

Measured with calibrated equipment, lab conditions. After a fine adjustment, the best results i obtained is with the following error:

Power source(lab) - Voltmeter(red digits) - measured value with calibrated equipment (all values in V, Iload=0.06A):

0.3 - 0.00 - 0.285

0.4 - 0.41 - 0.393

0.5 - 0.51 - 0.493

0.6 - 0.58 - 0.594

1 - 0.97 - 0.994

1.5 - 1.55 - 1.496

2.5 - 2.50 - 2.497

3.3 - 3.33 - 3.292

6 - 5.98 - 5.994

9 - 8.97 - 8.995

15 - 15.0 - 14.997

30 - 30.0 - 29.998

45 - 45.2 - 44.999

60 - 60.4 - 59.997

I tuned to this accuracy for 0-30V, probably you can make it more accurate on other ranges by fine adjustment.

[CPUDOCTHE1.]

We ordered one from China pre-made. It goes up to 30V and 10A. It was less than $70. Perhaps not as much fun as making your own, but a LOT easier. It has adjustable voltage and current. We used it to anodize aluminum.