Introduction: Selfmade Continiously Adjustable Step Up Power Supply
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.