1. First of all, the motor is concentric across 10 slot and 12 slot. Change it to two slots across 1 1 slot, and see how small the speed of the electric drill is after the change. Changing the single-speed motor to low speed will cause insufficient power of the electric drill.

2. Secondly, the voltage of the lithium battery electric drill is 12 volts, which is slightly lower. Several diodes are connected in series with the lithium battery.

3. In the end, the voltage drop of each diode is about 0.7V, and three to four diodes can drop two to three volts, plus a double-pole double positive switch.