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DIY Lab Bench Power Supply 30V 6A 180W [Build + Tests]

Hello, today I am going to show how you can
make a very handy variable voltage and current power supply. It can deliver from 1.5V up to 30V and has
a max power of 180W. Max current can go as high as 10A under the
max power limit and minimal as low as 300mA. It has active cooling and components have
big enough heatsinks to deal with the produced heat while operating.

And all of this costs only around $35. So stay tuned if you are interested in how
make one yourself. First, we need to place all these parts somewhere. For this, the plastic electronic component
box is a great solution. Choose a bigger box. It will be easier to install everything inside. Also, more space will provide better airflow. These four rubber standoffs will lift the
power supply that the air could go in from the bottom. To power everything, we need the 36V 5A power
supply, which has over-current, overload, and short-circuit protections. To get variable voltage and current we need
something like this 300W step-down module.

Two potentiometers control voltage and current,
but they are integrated. So we will need to replace them with two 100k
Ohm multi-turn potentiometers and caps to get convenient control. These banana sockets will deliver the final
output power. The small step-down module will provide constant
12V. It will power the voltmeter and ammeter display,
which has a max working voltage of 30V and max measuring current of 10A. From the same 12V, we will also power this
silent 2000 RPM fan. So let’s start with the front, we need to
make a square hole for the display, two holes for the potentiometers, one for the power
switch and two for the banana sockets. For smaller 5mm holes, the regular metal drill
bit will work just fine. Bur for the bigger holes, like 9mm and 15mm,
you need a step drill bit. To cut out a square hole, for me was quite
annoying as a tool like a fretsaw doesn’t fit here. So, I just drilled multiple tiny holes around
the markings, cut out bigger pieces and sanded to the right size, that display would fit. On the back, we need to make holes for the
fan.

It will exhaust hot air from the inside. And of course, more holes to mount the AC
power socket. With that done, we should plan the inside
layout for the components. You want like AC connectors of the power supply
to face the back and potentiometers of the step-down module to face the front. To secure the components, we need to drill
holes for the M3 screws and countersink them. In the front, we can make many 4mm holes,
through which the air will go in. With the main holes done, now we can make
secondary holes for the rubber standoffs. With all screws in place, now we can add components
and measure required wire lengths. Don’t worry I will show how everything connects
later in the video. But before connecting, we should de-solder
both integrated potentiometers, which on this module are 100k Ohms. I already de-soldered and extended one for
testing purposes, so I have only one to go. We need to add extension wires, which will
go to the new multi-turn potentiometers. The middle wire from the module goes to the
bottom connector on the potentiometer.

Canon EOS 30V

The top wire goes to the middle connector
and the bottom wire goes to the top connector. This way you will get that rotating potentiometer
clockwise voltage or current increases and counterclockwise decreases. Now we should start connecting everything. When securing AC power wires, always connect
ground wire, it’s a very important safety feature. For quick connection to the onboard AC socket
and power switch at the front, I used these wire crimp terminals. On them, I added some heat-shrink tubing for
the insulation. With all components in place, we can start
wiring the circuit. There will be 4 wires going from the 36V power
supply. Thick (16AWG or thicker) wires go to the main
300W step-down module and thin wires to the additional module. Now is the time to adjust the output voltage
of the additional step-down module. This means turning on the power supply. You have been already warned that this includes
AC wiring, so if you don’t have proper experience and knowledge of working with it, please don’t
try to make this project.

With second disclaimer aside, when the step-down
module is ON, we need to adjust output power to 12V. If you are using high RPM fan, you always
can reduce voltage to something like 9V to get acceptable noise levels. Now we reach the final wiring step. As this gets pretty hard to follow where what
is connected, I will draw a simplified view of it. So far we have connected live AC wire which
goes from the onboard socket through the power switch to the power supply. The neutral wire goes to the other terminal
and ground wire to the ground connection. Two thick wires go to the main step-down module
and two thin wires to the secondary module. To it, comes wires from the fan and two thin
wires from the display. The third thin wire from the display, which
is usually yellow, goes to the red positive banana socket. To this same socket goes positive output of
the main step-down module. Finally, black thick wire from the display
goes to the negative connector of the main step-down module, and red thick wire to the
black negative banana socket.

And that’s it, the circuit is complete. You additionally can fine tune voltage and
current readings with these two integrated potentiometers. With few final additions, the build is complete. The last thing that we need, is to make a
few banana plugs with alligator clips for quick and easy testing. Now, few accuracy and load tests. So, what can I say, as all parts cost only
around $35, I think it gives good value considering the accuracy and performance of the power
supply. For me, this device will hugely ease up testing
of all sorts of electronics for my future projects. So if you are looking for a cheapest way to
get above average accuracy and performance, DIY power supply like this might be the answer
for you. If you liked this video give it a like and
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