This post is a work in progress.

Bought a cheap project box. Paper tape and caliper allowed for quick sketch of component location.

I had a chinese all in one PSU which acts as a buck converter down from 40V inputs.

My requirements:

  • Up to 20VDC output
  • 4 amps
  • Small, 230VAC powered
  • Optional external DC power (via solar panel, for instance)

Final design is quite rude. The PSU takes any input. AC comes from a 24V 4A PSU, DC comes from independent inputs. A 3 way switch will take care of chosing where power comes from.
There's also a small power switch for the AC input.

That's it!

Front view
Back view
Ugly dremel cuts! These will clean up nicely later (trust me)
Work in progress in a 140cm desk :-(
Heavy gauge wiring.
More details
Finished product, acting as a proper PSU :-)