Features: 1. This module can protect lithium battery from burnout during charging or discharging. 2. This product can provide many guard functions including overcharge guard , overdischarge guard , short circuit guard and overcurrent guard. 3. Suitable for 3.7V or 4.2V lithium battery. 4. Maximum working current is 3A. 5. The moduleis made with electronic components, sturdy and stable. Specification: Over Charge Detection Voltage: 4.28 ± 0.05V Over Charge Release Voltage: 4.26 ± 0.05V Over Discharge Detection Voltage: 2.5 ± 0.1V Overcurrent Detection Current: 1-3A Overcurrent Guard : 3.2 ± 0.2A Size : 12.6x10.2x2.1mm Weight: 0.34g Wiring method: B- connected to battery negative B+ connected to battery positive P+ Connect the charger/load positive P- Connect the charger/load negative Applications: 3.7V lithium battery 18650 Charging module DD04CVSA DD05CVSA Module Note: Please activate the board when charging for the first time. Otherwise there is no voltage output .