This is one of my favourite projects, I learned a ton about working with Bucks, FETs, and Lithium cells.
For my EE graduation project, I built a compact UPS from scratch using LiFePO4 cells, a BQ76930 BMS, and an ESP32 for control. The goal: a safe, efficient backup supply that can run 30 W loads for two hours.

Features
-LiFePO₄ battery pack with cell monitoring
-CC/CV buck charger
-4 A current-limited discharge path
-ESP32 + I²C BMS telemetry
-Undervoltage, overcurrent, and overtemp protection
-12V, 19V, and USB-PD outputs
-88–89% efficiency under load
-Auto-shutdown on unsafe conditions

We didn't quite manage to finish all goals before the deadline, as always (lol).
The only remaining problem lies in the connection of the pack- to the general ground. This fault has lead to incorrect current readings, and charging not working as intended.
Future additions: solar charging, web UI, and smarter PD profiles.

We have posted all kicad files and further documentation