Semi-pseudonymous maker "LeoDJ" and colleague "Techbeard" have built a USB power supply that's capable of a 1.7kW total output, split across 24 USB Type-C ports and four USB Type-A ports.
"Now introducing: PDBrick! 1.7kW worth of raw USB-C PD [Power Delivery] power," LeoDJ writes of the chunky metal box festooned with USB ports. "The whole project was fuelled by initially finding really cheap DC-to-PD [Direct Current to USB Power Delivery] modules on AliExpress. And for cheap but powerful power supplies, there was basically only one logical choice: used server power supplies.
"[Just for fun], I did a basic CAD mock-up of how the modules and PSUs could fit together. It was too stupid and cheap to not give it a shot."
With a handful of 64W and 100W USB Power Delivery adapters in hand, and a thermal camera to check that the low-cost boards weren't going to overheat under a sustained load, the pair set about building the power supply — arranging the USB PD modules into a 4×5 array in a housing with PCB front plates, vented to allow the server PSUs to draw air through the chassis and cool all the components.
"Four rows of five 65W modules are screwed onto aluminum strips with thermal pads in between," LeoDJ explains. "These strips are then inserted into two 3D-printed side rails, which are then screwed to the front panel. This is also the thermal solution. Because it should almost never happen that all modules of a row are fully utilized, the heat should spread and thus get carried away by the airflow better."
The heatsinking system proved effective, to the point it made soldering a challenge, and the hardware was attached to a backplane PCB — with what LeoDJ describes as "wonky speed holes" for airflow. Everything was then fitted into an aluminum chassis, with an OLED panel and an Espressif ESP32 microcontroller reading SMBUS data from the low-side power supply for statistics display.
"I noticed that the values coming from the PSU were pretty hit & miss," LeoDJ admits. "Especially during light loads. So I simply used the values that matched the actual values closest and doubled them."