Let us first examine the physical formula determining charging efficiency: Energy W (which may be regarded as battery capacity) = Power P × Time T; Power P = Voltage U × Current I. It is thus evident that, for a fixed battery capacity, the magnitude of power dictates the speed of charging; greater power yields shorter charging times. Based on the formula Power P = Voltage U × Current I, it follows readily that to enhance charging speed and reduce charging time, the following three approaches may be employed:

1. Increase current while maintaining voltage;

2. Increase voltage while maintaining current;

3. Simultaneously increasing both voltage and current also achieves rapid charging.

Regarding the relationship between power, current, and voltage, we might draw a simple analogy: filling a bathtub with water. Increasing voltage and current is akin to boosting the volume of water delivered per unit time and accelerating the flow rate. When either one or both parameters increase, the filling efficiency naturally improves, and the bath fills more rapidly. The speed at which it becomes full (or fully charged) also sees a significant boost. Currently, many manufacturers' fast-charging solutions rely on increasing voltage (or simultaneously increasing both output voltage and current) to achieve this.