This module is suitable for 3.7V lithium batteries in 2-cell or 3-cell configurations. Short-circuit settings enable default 2-cell operation. When using 2 cells, the built-in battery balancing function is highly practical. Input options include Type-C port or soldered wires. When connected to a Type-C fast-charging power source, the module automatically adjusts charging voltage for enhanced efficiency. For soldered wire input, the input voltage must be lower than the battery voltage; otherwise, the module will only operate in boost mode. Input: Selectable Type-C port or solder wire input. When connected to QC fast charging via Type-C, it automatically adjusts the charging voltage to improve efficiency. For solder wire input, the input voltage must be lower than the battery voltage (battery voltage × number of series cells). Output: Supports 2-series and 3-series configurations. Batteries require a protection board. To switch from the default 2-series to 3-series, short the shorting points and remove the adjacent resistor. The balancing function is available for 2-series configuration. Connect the BM pin between the two series batteries (note: balancing speed is limited; ensure consistent parameters between series batteries when using this feature). Current Settings: The green arrows in the diagram indicate the current settings for two parallel circuits. Default values are 100K (0.9A) and 180K (0.5A). Resistors can be removed or replaced as needed. Current calculation formula: Current = 90000 / Resistance Value.