I went on a trip with my new 14″ MacBook Pro and a couple small (30W, 60W) USB-C power supplies. I didn’t plan to use it heavily, and smaller power adapters have always worked to trickle charge previous MBPs. The battery died while it slept and no power adapter would charge it. It would not turn on until I returned home and plugged it into the 96W power supply that came with it. Lesson learned?