I've created this case for a QEBIDUL LM 2965 buck converter to be used to power a Raspberry Pi. The buck converter will do 5 volts at 5 amps.
I didn't like being constrained by only one mounting orientation for the v-slot rail so I created a new version that has a couple of channels for v-slot rails to be interlocked with the main model to allow orientation in the v-slot rails on your printer on either the narrow side on top of or under the v-slot or on the back part of the box so you can mount the box on the side of your extrusion with the box standing up or hanging below the v-rail.
The interlocking v-rail piece is a pretty tight fit. I printed it initially with supports, but if you use supports keep the density under 15 percent and only use lines, not grids or zigzag otherwise you'll have a pretty tough time taking the supports off and getting the interlocking channel cleared enough to accept the v-rail interlocking piece.
I added v-slot mounting rail to the box so you can attach it to the aluminum extrusion.