Note 1: To successfully start the electric drill, you need 4pcs 10C-20C power batteries, or 8pcs 5C-10C power batteries, 0V and 12.6V connecting wires, and use copper wires of more than 3 square millimeters (no nickel sheets!! ).
Note 2: Wiring 0V, 4.2V, 8.4V, 12.6V strictly in accordance with the diagram, do not touch any components on the board when welding the wire, and do not intentionally short-circuit.
Note 3: When the battery is welded for the first time or is being charged, as long as a single battery exceeds 4.2V, the 430 resistance will heat up and discharge (discharge to about 4.19V to stop heating). If the 430 resistor is very hot (you can't touch it when it is too hot), please check whether it is connected to the wrong wire.