The successful start of the drill requires three 15C-20C power battery, or six 10C-15C power battery (ordinary 18650 can not start the drill). Strictly according to map wiring 0V, 4.2V, 8.4V, 12.6V, 16.8V, do not deliberately short circuit. When the load of the brush motor is used, try to connect a non-polar capacitor (with stand voltage above 25V, capacity 10uF-100uF) to the motor's positive and negative terminals to prevent the reverse spike from the motor. Break the MOS tube. Groups of batteries in series, please ensure that the voltage of each group of batteries,if not the same, please fill each battery separately and then use in series. The Discharge test, the voltage drop faster battery that group is poor battery. Product Description:3S 12.6V 40A lithium battery protection board with Balance for Screwdriver Scope: Nominal voltage of 3.6V, 3.7V lithium battery (including 18650,26650, polymer lithium battery) Charging voltage: 12.6V-13.6V 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. Name: Protection Board Colour: green Material: PCB Package Contents: 4 * Protection Board Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm. Protection Board PCM Battery Protection Module Battery Protection Board