Features 100% Brand new! 4 string 40A lithium battery protective board, comes with recovery function-auto recovery. Enhanced version, applicable to electric drills with starting current below 80A, power below 230W(no balanced function). Integrated 10 imported low internal resistance MOS tubes, continuous discharge 40A, suitable for electric drills, sprayers, LED lights, low power inverters, etc. Ideal 4S 40A 4S40A li-ion battery 18650 charger BMS PCB protection board with balance for drill motor 14.8V 16.8V lipo cell module. Specifications Charging Voltage: 16.8V~18.1V Continuous Discharge Current (upper limit): 40A(If the cooling environment is not good, please reduce the use of load current.) Continuous Charge Current (upper limit): 20A Size: About 45x55x3.4mm/1.8x2.2x0.13" Scope: Nominal voltage of 3.6V, 3.7V lithium battery(including 18650, 26650, lithium polymer battery) Attentions 1. Please allow tiny size deviations due to human measurement. 2. This item is an enhanced version BMS PCB without any equalized charging. 3. The successful start of the drill requires four 10C-20C power battery, or eight 5C-10C power battery(ordinary 18650 can not start the drill!!). 4. Strictly according to wiring guide 0V, 4.2V, 8.4V, 12.6V, 16.8V, do not touch any components on the board while soldering the wire to avoid short circuit. 5. When soldering the battery for the first time or when charging, as long as a single battery exceeds 4.2V, the "430" resistor will heat up and discharge (stopping heating when discharged to 4.19V or so). If the "430" resistor is severely heated (it's too hot to touch), please check if the wrong line is connected. 6. When connecting 4 groups of batteries in series, please ensure that the voltage of each group of batteries is the same. If they are different, please charge each group of batteries individually and reconnect it in series. In the discharge test, the battery with a faster voltage drop is a poor battery. Package Included 1 x 4S 40A Protection Board