Introduction: 12 Volt 50 Amp Bench Integrated Power Supply

A lot of the power supplies that you see on the internet that can only supply 12 volts do not pack very much power. They can only supply a few amps. Some of my projects required a lot more current than most ATX or other bench power supplies could handle! What if I told you that you could build an awesome bench power supply that is literally part of your desk that could supply up to 50 amps? Well, in this instructable, you will learn how to do exactly that. This power supply was actually built from an old RV power converter and integrated into a part of my desk with a piece of plywood. It can supply the horsepower (Wattage) for those projects that need a lot of current. It can also power my Ham radio station! The video below will compliment this instructable with a demonstration of this power supply in action. It will also show some ham radio stuff.

Lets Get Started!!

Step 1: Tools and Materials

The most important part of any project is gathering the supplies you will need to make that project. The parts you will need are:

  • An RV Power Converter (Look to the next step for how to get one.)
  • A piece of plywood.
  • A light-switch and cover.
  • A blank wall cover (Like a light switch cover, but no holes)
  • Nuts and bolts
  • Crimp on wire connections.
  • Wire nuts
  • A plug and wire
  • Wire (High and Low gauge)
  • Wood Screws

The tools you will need are:

  • A drill with bits
  • A jigsaw
  • A soldering iron
  • Wire Cutters
  • Wire Strippers
  • Wire Crimpers

Step 2: Getting the RV Power Converter

The RV power converter is the most important part of this project. It is the heart of your power supply. You can get these from various different places. You can get them on amazon for about 100 dollars and they will give you the 50 amps needed. If you need a slightly lower current capacity and want to save some money, then you can also find lower power output 12 volt power supplies. In fact, the RV power converter for this project can be replaced with any power supply you want, as long as it has an input and an output.

I was able to get my RV power converter practically for free. While on vacation, the power converter in my families RV stopped functioning. Because I was away from my lab at home, I was not able to find or fix the problem, so we had to buy a new converter. After we got home, I was able to diagnose and fix the issue with the old power converter and get it working. That is the power converter that is used for this project.

You can watch how I fixed it here:

Step 3: The Desk

Your workbench, or desk, is the place that your power supply will be mounted at. It is important to find a spot on your desk to mount your power supply before continuing through this instructable. On my desk, there is an alcove on the side that is just big enough for an RV power converter, so it will be perfect for this project. Not all desks will look the same as mine, so you will need to modify your project to fit your own needs. The picture above is the alcove on my desk where the power supply will be mounted.

Step 4: Cutting the Faceplate

The face-plate of this power supply is what hides the ugly power converter and holds the switch and connection terminals for the power supply. If you do not have an alcove on your desk, you may just want to cut a whole wooden box. In my case, I measured the dimensions of the alcove of my desk to cut a square piece of plywood that would fit there. You will then need to cut and drill some holes in your face-plate to mount the components. For the power switch, you will need to trace a square hole in the plywood about as big as the back of the light-switch. To cut out this hole, drill each of the corners with a drill bit the size of your jig saw blade. Then, use the jigsaw to connect all 4 holes so the inside of the plywood falls out. After that, drill some pilot holes on the front of the face-plate to connect the light switch too. You can now connect the light switch to the plywood with the screws that came with it.

After the switch part of the face plate is made, its time to add the terminal half of the face plate. This part is how you connect your project to the power supply. To do this, you will just need to drill a few holes. Start by taking your white plastic wall cover, and center it on the plywood where you want it mounted. Then, use a drill to screw the wall cover down to the wood. After this is done, you will need to find a drill bit the size of the bolt you want to use for connection, and use it to drill two holes symmetrically in the middle of the wall cover plate. You can then slide the two bolts into the holes.

Step 5: Wiring the Hot Side

The hot side of the power supply is the part that connects to 110 volts AC. To wire this, first you will need to find a power cord. The power cord will connect your power supply to the AC mains. You will need to find the black and white wires coming from the power cord, and identify hot and neutral. Neutral is the white one and hot is the black one. You will need to connect the hot wire to one pole of the switch and the neutral wire to one end of the power supply's inputs. Connect the other one of the power supply's inputs to the other pole of your switch. Make sure to connect all the ground wires together for safety purposes. Use wire nuts to connect different wires together.

Step 6: Wiring the "Cold" Side

The cold side of your power supply is the twelve volt side. You can start by connecting two wires to the positive and negative holes of the power supply using solder. Remember to use very low gauge wire to prevent electrical fires! These wires can go directly to the two bolts that are going to the power output of the supply. Make sure to use washers. When you want to connect wires to the bolts, use crimp on wire connections. Just add a crimp on connector to the end of a low gauge wire, and use a crimping tool to secure it. It can now connect to any bolt. In addition to this, I also connected two other wires going to the positive and negative rails of my power supply to go to my ham radio. My ham radio needs 12 volts at a high current when transmitting, so directly connecting it to my power supply is really helpful. It also frees up the front terminals of my power supply for other things when my radio is in use.

Step 7: Integrating It Into the Desk

To integrate this power supply into my desk, the first step was to clear my messy alcove of all the rubbish that was there from my projects. Then, the RV power converter can be slid into the alcove. The face plate can then be secured into the front of the alcove using wood screws. To secure it, drill a hole in the top of the desk into the the piece of plywood and add a wood screw in the hole with a drill. You will also need to add another screw to the opposing side of the plywood but on the bottom. This will make sure that the face plate of your power supply will stay in place. Now, the power supply is actually part of your desk/workbench.

Step 8: Testing It!

This power supply performs very well. The voltage of the power supply doesn't even drop when my 10 meter radio is transmitting at full power! It also can easily supply many amperes. It looks very nice as part of my desk.

Step 9: What to Use It For

This power supply can be used for many different purposes. One of the best uses that I have for my power supply is running my ham radio setup. It powers my radio and 100 watt power amplifier with ease. It is also very useful for charging batteries. I can have it hook up to my all purpose battery charger and charge almost any battery. Having this power supply is the equivalent of having a car battery on your desk that will never run out of charge. That being said, it has a wide range of uses.

Well, thanks for reading and good luck building your power supply!

Be sure to vote for me in the power supply contest!

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