External lithium battery and USB charging The expansion board accepts an external 3.7V lithium battery and supports charging the battery through USB. The green LED indicates charging; when it turns off, the lithium battery is fully charged. The expansion board exposes all IO ports, enabling convenient access to multiple functions and various sensors. Designed for ESP32C3 SuperMini This expansion board is designed specifically for the ESP32C3 SuperMini development board and addresses limitations of the base board. Voltage options for VCC1 and VCC2 The default output voltage for VCC1 and VCC2 is 3.3V. If a higher voltage is required, short the PCB to set the output to the supply voltage of 3.7V. Dual power rails The expansion board provides two power supplies, VCC1 and VCC2, for improved power management and flexibility. Use scenarios Portable sensor projects powered by an external 3.7V Li battery with USB charging, leveraging all IO ports and sensor interfaces. Prototyping and development tasks on the ESP32C3 SuperMini that require access to additional IO and the option to adjust supply voltage. Field deployments or remote environments where two independent power rails (VCC1 and VCC2) help manage power for different modules while keeping battery charging via USB.