MH-CD42 CD42 DC 5V 2.1A 18650 Lithium Battery 3.7/4.2V Charge/Discharge Protection Step-up Boost Converter Module for DIY Power Bank

Parameter:
Charging voltage: DA4.5V-5.5V (recommended DC5v)
Charging current: 0-2.1A
Charging quiescent current: 100uA
Full voltage: 4.2V ± 1%
Discharge current: 0-3.5A
Discharge quiescent current: 50uA
Discharge efficiency: up to 96%
Output voltage: 5V
Output current: 0-2.1A
Ambient temperature: -20~85 degree

The module comes with a lithium battery protection function (for lithium batteries without protection, with protection board

Overcurrent protection (OCP)
Overvoltage protection (OVP)
Short circuit protection (SCP)
Over temperature protection (OTP)
Charge and discharge power level 4 interval indication

Pin Description:
1 VIN: The charging port is correctly input + (DC4.5V-5.5V (recommended DC 5V)
2 GND: negative input of the charging port –
3 GND: Lithium battery –
4 BAT: Lithium battery +
5 GND: Output negative output –
6 VOUT: Output positive output +
7 KEY: Output enable trigger port (low pulse trigger)