Lithium Battery Charger Protection Module (BMS) 4S 20A 16.8V

From the shop's description

Features: High-accuracy voltage detection circuit Terminal of the charger using high voltage device Built-in three-stage over-current detection circuit Can control the battery charge and over-discharge Low standby current consumption Small size Simple writing, circuit connection, and installation Specifications: Overcharge voltage range: 4.25V-4.35V±0.05V Over discharge voltage range: 2.3V-3.0V±0.05V Charging voltage: 16.8V to 17V Upper limit working current: 10A Upper limit instantaneous current: 20A Quiescent current: <30µA Internal resistance: 45mΩ Operating temperature range: -50℃ to +50℃ Storage temperature range: -50℃ to +80℃ BMS Solder Instruction: B+: connected battery positive B1: connect point between battery 1 and battery 2 B2: connect the point between battery2 and battery 3 B3: connect the point between battery 3 and battery 4 B-: connect to battery negative P+: connection charge / discharge positive P-: connection charge / discharge negative