Selfmade Continiously Adjustable Step Up Power Supply

About: Hi, my name is Jan and I am a maker, I love building and creating things and I am also quite good at repairing stuff. Since I can think I've always loved creating new things and thats what i keep on doing ti...

When you are working outdoors and don't have a generator a 12V battery like the one you have in your car is a good power supply. But sometimes 12V just don't cut it. For this I put this step up converter together. It can take any voltage from 10V to 32V and convert it into a higher voltage up to 35V. With this you can charge your 14V cordless drill, your 19V laptop or a 16V LED lamp.
You can also buy those things for around 20€ but I wanted to have one that enables me to continuously adjust the voltage and through the two built in voltmeters and an amperemeter I can also monitore the power consumption and the condition of my battery.

Today I will show you how to build one yourself.

Step 1: What You'll Need

To do it yourself you will need...

  • a dc-dc stepup converter(mine can handle up to 100W with the attaced passive cooling and 150W with a fan)
  • some wire (1,5mm^2)
  • a fuse holder + 10A fuse
  • a voltmeter + amperemeter
  • a second voltmeter for the output
  • a knob
  • a ballpoint pen with a thin ink container
  • two 5,5 X 2,1mm DC sockets

The tools are the following:

  • a pair of pliers
  • a wire cutter
  • a cutting knife
  • a measuring tool

as well as

  • a drill or dremel tool
  • a soldering ion


  • a hot glue gun

Step 2: Prepare the Housing

Decide how you want to mount the components and apply masking tape to the plastic surface. Use your measuring tool and a pencil to mark the holes. Don't for get to add a few ventilation holes as well.
Then use your dremel tool to cut out the rectangular holes for the Voltmeters and drill a hole for the ink container of the ballpoint pen to go through. It will be used to connect the knob to the boards trim potentiometer.
I also drilled small holes in a circle around the main hole. The plan is to add a small bracket that goes through the knob and into the holes so you can scure it after you adjusted the voltage. Thats why you have to drill two holes through the knob as well.

Step 3: The Potentiometer

As I already mentioned: the knob will be connected to the boards trim potentiometer. You might want to have the knob in the middle of the enclosures front but it is not in the middle of the board. To have it underneath the knob you need to remove it and place it somewhere else. Heat up the soldering joints with your soldeeing ion and pull it out of the pcb. Attach a few centimeters of wire to it and connect the ends of them to the board again.
Now you have a resistor that you can place anywhere else.
Start prepearing the ink container.
To fit the big knob onto the thin plastic tube I wrapped it with duct tape.
To make it fit onto the potentiometer I drilled into the inside of the ink chamber to widen it. This solution is temporarily and I will update this Ible as soon as I found a better one.

Step 4: Time to Solder

The converter itself has only 4 screw screw terminals for the input and the output. The other components make the wiring a little bit more complicated.
You want to connect the volt+amperemeter as well as the fuse and a DC socket to the input and the second voltmeter and the output socket to the output.
To do this you need to connect the thick and the thin black wire of the volt/amperemeter to the negative side of the input socket and the thick blue wire to the negative input of the converter. You solder one side of the fuse holder to the positive pin of the output socket as well as another wire that goes to the boards positive input.
On the ouput side you simply connect the Voltmeters wires to the output socket.

Step 5: Put It Together

Put all the components into the enclosure and arange the wires in a way that they won't disturb the air citculation too much. Hot glue the trim potentiometer under the whole and attach the knob and close the housing.

Step 6: Use It

Now you have a nice little device that. can turn a 12V battery into a multi purpose power supply.
Make a few adapter cables for the input and output so you can connect it to a variety of devices and power sources and use it.
I hope this Ible was helpful to you and I would like to know what you think about it.



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    6 Discussions


    3 years ago

    I am back and yes also I am busy to build a bench power supply

    But with an computer power supply. And the 150watt pcb I wanted to use as a power supply for a 20w led,for my new solder station.

    But my question is, how high Wil the current be,because I saw a picture from u,at 12v and it whas only 300ma

    3 replies

    The off-load current of the board is around 25mA or do you mean the current with a 20 Watt load. If it is a regular 12V LED-chip it will be 20W/12V=1,7A probably even a little bit higher because of the boards efficiency which is around 90%.

    One thing you have to explain to me is why you are using a computer power supply and a step-up converter to power such a small load.


    O no my dear friend, the 150w has nothing to do with the atx power supply, that I am going to use for my soldering station as a 20w led driver with another potentiometr outside the enclosure

    But my question is how much current it has as a module
    if I use my calculation-power devided by voltage 150w*12v=12.5a
    That is in my eyes impossible
    I did not find the datasheet of this module
    Sorry if I whas not clear.


    The product page states that the maximum output current that this board can supply is 6amps. The highest possible input current without a bigger heatsink is 10amps.