Construction of a bench power supply using the Rui Deng DPS5020-USB


Tags: electronics

This construction project ended up taking almost a year from start to finish! I bought the Rui Deng power supply modules in August of 2017, and finally finished constructing the power supply in August 2018 :D

August 2017

I purchased the first DPS5020-USB unit directly from RuiDeng on AliExpress. The version I bought comes with both USB and Bluetooth connectivity, although only one can be used at a time.

The DPS5020 can take input voltages of up to 50V, and provides output voltages from 0 to just below your input voltage.

Front of the packaging
Back of the packaging
Contents of the packaging

I bought this Meanwell 500W 48 power supply off eBay for £28. Bargain!

Power supply used as input to both the DPS5020s

September 2017

In September I went to the National Radio Fair, where I purchased some rubber feet for the case, as well as another power supply, a CUI Inc. VF-S250-12A with 12V output.

November 2017

To determine where to make cuts in the case, I modelled the case in Autodesk Fusion 360. As I didn’t want to mount the contents directly to the bottom of the case, it also allowed me to determine the dimensions for a metal plate to screw to the inside of the case to mount the components to.

Fusion 360 render of my model of the case
Drawing of front panel

Cutting the holes, and honing them to the correct sizes took quite a considerable amount of time…

After making appropriate cuts to the front panel, it was sprayed with primer, purchased at the UK kit car show for a very reasonable price.

Spraying with primer

Unfortunately, the weather was rather cold and this did not help with the drying of the paint…

A few coats of Mercedes black metallic paint were used, followed by a clear coat

Adding the colour paint

December 2017

Back at home for Christmas at my parent’s, it became apparent that the crimps I’d done weren’t very good. At all. Without too much effor it was possible to pull them off. Fortunately my dad had a superior crimper, so I recrimped all the terminals

Superior crimper

Finally on boxing day the unit was fired up for the first time! the front panel bits weren’t fully pressed into the case as at this point I realised the paint job was insufficient and would have to be redone.

Everything in place
First time firing the unit up
Back of the unit (yes, the fan hole is slightly misplaced due to a miscalculation

May 2018

Due to the previous paint job on the front not being very good (the pain never really set, think this may have been due to using mismatched primer/paint/clearcoat), I resprayed the front with some Ford Focus ST170 blue paint I had laying around.

Internals of the PSU, Meanwell and CUI power modules side by side, stacked RuiDeng boards at the front
Here you can see the 2 DPS boards mounted on top of each other on threaded rod

The bench power supply was essentially complete at this point!

August 2018

To test the power supply, I purchased an electronic load off AliExpress. I couldn’t completely test it to it’s limits as the load has a maximum draw of 175W, but that is far in excess of what I would normally draw.

Power supply connected to electronic load
DPS display while under load
Electronic load display

Altogether this was a satisfying project, but when I started I had no idea it would take this long to complete!


Item Product Supplier URL Part Number Quantity Price ea Total price
Case 3U 10.5 inch rack mount 300mm vented enclosure chassis case All Metal Parts 1 £54.16 £54.16
Case feet Rubber feet MA components 4 £1.50
Mounting panel Mild Steel Metal Sheet Guillotine Cut 100mm-100 penninemetalsdirect eBay 1 £4.68
Power supply Meanwell SP-50048 random eBay seller 1 £29 £29
Power supply CUI Inc. VF-S250-12A radio fair 1 £10 £10
Rui Deng DPS5020-USB AliExpress 2 $48.99USD $98
Carlingswitch DPST, On-Off Rocker Switch Panel RS 664-553 1
Hirschmann Test & Measurement, Red 4mm Socket, Nickel Plated, 60V dc, 35A RS 738-351 3
Hirschmann Test & Measurement, Black 4mm Socket, Nickel Plated, 60V dc, 35A RS 738-345 3
Hirschmann Test & Measurement, Green 4mm Socket, Nickel Plated, 60V dc, 35A RS 738-389 1
C14 IEC Plug RS 202-4963 1
crimp connectors
Threaded rod DURATOOL ST01030100081FA Studding, Threaded, Steel, Zinc Plated, M3, 1mm Pitch, 1m Length CPC 517320
Spray paint
Assorted hardware, nuts and bolts etc

Tools used