Description of 2S Lithium Ion BMS Board Lithium batteries is now very popular of their superior performance. But for imbalance charging, over discharging, over charging and short-circuit may damage the battery performance. To optimize the battery performance, maximize lifetime and ensuring safe operation is mandatory. Only a well-designed Battery Management System (BMS) can protects and monitors a lithium battery during charging and discharging.   Feature: Over and Under Voltage Protection Overcurrent and Short-Circuit Protection Balance Charging   Note: Output terminal (P & P-) will be at 0V initially after attaching batteries between (B & BM) and (B- & BM). You need to put external 8.4V between P & P- for about 3 seconds to "activate" the BMS board. After that, P & P- will provide voltage output according to battery voltage.