A Custom Power Supply with 18650 Battery Charging
Max Imagination's benchtop power supply provides 0-36V, plus USB outlets and charges 18650 batteries.
A benchtop power supply is one of the essential tools for electronics tinkering. While you could simply buy one, this project by Max Imagination shows you how to create your own, with a combination of new and recycled materials. This particular supply can also charge 18650 cells and has a dual USB outlet, making it even more generally useful than a typical purchased supply.
The heart of the design is a 100-240V AC to 36V DC converter, which provides DC power. This is then regulated by a 0-50V, 5A step-down module that lets the user set the voltage and maximum current output as needed. Battery charging is handled by a pair of TP4056 charging boards, attached to a dual-cell battery tray that is modified so that the cells are no longer in series. This allows the cells to charge independently of one another.
Along with the circuitry setup, the video below shows how the housing was cleverly made with cases from pair of DVD -ROM drives. These are heavily modified to serve as the new enclosure, including a large hole in the top for a cooling fan. Max adds a new custom grate to the fan for protection. Rather than having the fan run all the time, it’s hooked up to a temperature sensing circuit so that it only turns on when needed.
The build video has lots of tips, tricks, and advice, including the fact that you need to hook up the AC supply correctly in order to avoid electrical shocks. As always, be safe if you choose to attempt something like this!