- Auto end of charge: When the charging current falls to 100 mA after reaching the final float charging voltage, the charge cycle ends automatically. This helps prevent overcharge and maintains battery health. - Auto power-off on light load: If the load current remains continuously below 50 mA, the output is switched off to save energy and reduce heat. - External key control and 5 V output: The unit supports an external key connected to the K pin and the negative output terminal. Short press to turn on the power indicator and enable the 5 V output. Press twice quickly to turn off the power indicator and disable the 5 V output. - Automatic restart on low battery: If the battery voltage drops below 4.1 V, the charging cycle restarts to restore full charging. - Benefits and use scenarios: • Safe, automatic Li‑ion charging with clear on/off control for the 5 V output, suitable for compact devices, DIY charging setups, and integrated power solutions. • Compatible with external switching for remote or panel-mounted control, enabling simple user interaction without full app or display interfaces. • Use case 1: Home DIY battery charger for small electronics that require a controlled 5 V output and automatic cut-off. • Use case 2: Standalone charging station for portable devices where a manual on/off switch is desirable for energy saving. • Use case 3: Embedded power module for projects using Li‑ion packs, with safe auto restart when voltage falls to a safe threshold.