Why won't the car start when the battery is dead?

[OJoel]

The car won't start when the battery is dead due to battery depletion. Here is an introduction about battery depletion: Introduction: Battery depletion, commonly referred to as insufficient voltage, involves both the power source and the electrical appliances. Definition: It is generally a colloquial term for insufficient voltage (or power). It includes both the power source and the electrical appliances. For example, when the battery power is insufficient or the internal resistance of the power source is too high, the electrical appliances cannot obtain the rated voltage required for normal operation and operate under low voltage conditions. This is called battery depletion. Additionally, if the car's generator charging system malfunctions, preventing timely replenishment of the battery power consumed by the starter and other circuits, it is also referred to as battery depletion.