A BMS is a battery management system often used in a medium or large format lithium-ion battery pack. A BMS is a circuit board that provides protection, monitoring, balancing, and other high-level functionality for a battery pack.

Specifications

• Continuous discharge current (upper limit): 40A (if the cooling environment is not good, please reduce the load current use)
• Continuous charge current (upper limit): 20A
• Charging voltage: 16.8V – 18.1V
• Nominal voltage cell of 3.6V, 3.7V lithium battery (including 18650,26650, polymer lithium battery)
• Dimensions: 

Note:

1. Connect strictly according to map wiring 0V, 4.2V, 8.4V, 12.6V, 16.8V do not deliberately short circuit. 
2. When a motor brush is used, try to connect a non-polar capacitor (withstand voltage above 25v, capacity 10uF-100uF) to the motor's positive and negative terminals to prevent the reverse spike from the motor.

Documents: datasheet