Feature: 1. SUPPORT EXTERNAL BUTTON: Battery charger discharger module supports external button, connect the button to k point and negative terminal of the battery, short press can wake up the system, display the battery levels and turn on the 5V input. 2. SUPPORT CHARGE DISCHARGE: Lithium battery charge discharge module supports charging and discharging at the same time, when unplugging the input power, the output 5V will be turned off briefly. 3. AUTOMATIC CURRENT LIMITATION: When the input voltage drops in case of high current and power shortage, the module automatically limits the charging current so that the input voltage is not lower than this value. 4. STOP CHARGING DETECTION PROCESS: first judge whether the current is less than the set value, pause after a few minutes, check whether the voltage reaches the stop charging voltage, the 4 values of the stop charging detection voltage correspond to the 4 charging voltages. 5. SIMPLE INSTALLATION: USB A charge discharge module provides USB A female connector soldering position on the back, you can install the female connector manually. Specification: Item Type: Charge Discharge Integrated Module Material: PCB Input Voltage Range:5 to 5.5V Charge Stop Voltage:4.2 to 4.4V(Default 4.2V) Charging Current:0.1 to 3.1A Discharge Cut off Voltage:2.95V Boost Output Voltage: 5V to 5.15V Boost Output Ripple and Noise:<150mvp p Boost Output Current:2.4A Boost Conversion Efficiency:>90%(Battery Voltage 3.6V, Load 0.5 to 2.4A) Static Current(Boost Normally Open):<900uA Static Current(Boost Auto Sleep):<100uA. Package List: 1 x Charge Discharge Integrated Module1 x USB A Female Connector