Stackable/expandable USB (and 12V) charging station case

This is a set of elements to build a charging station for both 12V and USB charging. It consists of three basic elements:

• Bottom element (bottom_case.stl) for 5 USB chargers (use this one: https://www.banggood.com/DC-7V-24V-To-DC-5V-3A-USB-Output-Converter-Step-Down-Module-KIS3R33S-p-912110.html) and one 12V socket with a switch (use a standard snap-in switch for cars). A standard glass fuse holder is used.
• Intermediate element (intermediate_case.stl) for 5 USB chargers and one 12V socket, but no switch.
• Top cover (top_cover.stl)

They are screwed together using 6 M3 threaded rods and 12 nuts (one on top and bottom for each rod). On top, the nuts are recessed, on bottom the rods stick out (you need some play for mounting) and you can put the little covers (screw_cover.stl) on top of that for better looks and protection from scratching.

Due to popular demand (the people being me :p) I now added a set of models for a charging station with no 12V socket, only USB chargers. The concept and the build is the same, they are just narrower due to the socket being cut away. Use the _no_socket models. You can see how it looks as a part of a solar charging station on one of the pictures. I also used this set of connectors to build the station.

Print Settings

Printer:

Craftbot

Rafts:

No

Supports:

Yes

Resolution:

250 um

Infill:

25-33%

Notes:

Preferably use a transparent filament to see the lights of the USB chargers.
Supports should be placed in the 12V socket holes, switch hole and under the intermediate segment and optionally in the USB socket holes and fuse holder hole (depending on how good your 3D-printing setup is with bridging).

Flip the top cover and support only the nut recesses.

Post-Printing

Assembly

Print everything (1 bottom element and cover, 6 screw covers and the preferred number of intermediate elements (each adds 5 USB chargers)), preferably with transparent filament (transparent PLA, PET or polycarbonate) to see the USB charger LEDs.

Screw in the USB modules using short 2mm wood screws. The little nub at the USB opening is there to gude the led light to the front of the case (if you use a transparent printing filament).

Insert and screw in the 12V socket and the fuse holder. Snap in the switch in the bottom element.

Wiring is simple:

1. Connect all the negatives together and route the negative wire through the channel at the back.
2. Connect all the positives in each element together and connect them to the fuse, route the cable from the other end of the each element fuse to the switch and then the main power line back up, parallel to the negative. Look at the pictures for the general idea.
3. Fuse the positive main line separately at the source (unless you use a current-limited source, but even then you could play it safe). Use at least 2.5 mm2 of cable cross-section, if you use a 20A main fuse (do not exceed switch current rating).

Take a 1m piece of 3mm threaded rod, stack the wired elements, stick in the threaded rod and snip off the excess length, leaving about 5 mm to make the assembly easier. Screw together, taking care that there is no thread sticking out on top (you can add a drop of superglue in the top nut to prevent it moving on the threaded rod. Add and tighten (gently and cross-wise) the bottom nut and stick the screw cover on the protruding part of the threaded rod. See pictures for the concept.

Connect to power source, turn on the switch and marvel at the lovely lights ;) You now have Nx5 USB (and possibly N 12V) charger sockets (N being the number of segments) just waiting to be plugged in!

Category: Electronics