Big thanks to peterneuteboom on Thingiverse for the base model!

I wanted a clean and discreet charging solution for my BMW E46. While there are plenty of options that use the cigarette lighter, I preferred something that can be hidden when not in use and doesn’t require major modifications to the car.

I used these USB-C charging modules from AliExpress. (The mini version, the normal won’t fit) They accept an input voltage of 8–32V DC and provide a USB-C output. They appear to be well-built and include some basic protection circuitry.
Note: The cigarette lighter in the E46 is always powered, so expect a slight power draw — though the idle consumption should be minimal.

The modules are press-fit into the main body. Depending on your printer’s tolerances, the fit may be a bit snug, but this helps keep them securely in place.

I used 0.5 mm² wire for the module connections and 1.5 mm² wire to connect everything to the cigarette lighter. The cable lengths can be short, so routing them is easy.

To tap into the cigarette lighter power, I used piggyback spade connectors. The positive connector needed to be filed down slightly to fit properly.

For assembly, you’ll need:

• 5x M3x3x4.2 mm brass threaded inserts
• 5x M3x3 mm screws

Screw the small block to the inside bottom — it applies pressure on the charging boards to hold them in place when plugging in a cable.
Then mount the main body to its counterpart.

Installation note:
You'll need to remove the cigarette lighter unit from your car to access the wiring. A small hole should be drilled in the area marked here to route the cables.