Feature:1. The switching frequency is up to 1MHz, and the voltage loss is compensated in the quasiCV mode.2. With automatic charging function of battery internal resistance and tracking resistance.3. Protect battery voltage lower than input voltage and battery short circuit function.4. Strong adaptability to input power, limited drive capacity, overvoltage protection battery.5. Made of high-quality materials, strong and durable, has a long service life.Specification:Item Type: Liion Battery Charger Module4 Sections (4S) 16.8V Version: Input Voltage: DC 3 6V (recommended DC 3.7V 5V)Input Current: 1A (1A version)Charging Voltage: 16.8VCharging Current: 0.28A (1A version).Package List:1 x Li-ion Battery Charger Module