The MT3608 (also known as B628) is a very efficient boost converter that can deliver up to 24V at 4A.
It requires only 6 external passive components, and is readily available as a complete module for as little as $0.40.
For this test, I built the standard variable converter circuit from scratch and evaluated its performance.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
