Should the Car Battery's Positive or Negative Terminal Be Removed First?

[IrisLee]

When removing a car battery, the negative terminal should be disconnected first, followed by the positive terminal. Conversely, during installation, the positive terminal should be connected first, then the negative. If the positive terminal is disconnected first and comes into contact with any metal part of the car body, it effectively creates a direct connection between the positive and negative terminals, resulting in a short circuit that can damage the battery and wiring. Similarly, if the negative terminal is already connected and the positive terminal is being tightened, accidental contact between a metal wrench and the car body can also cause a battery short circuit. The same principle applies when jump-starting a dead battery—always connect the positive terminal first, then the negative. Electrical systems in cars operate on low voltage, direct current (DC), a single-wire system, and negative grounding. Low voltage and DC are straightforward—12V DC power supply. The single-wire system and negative grounding mean that the car's metal body serves as the common negative terminal for all electrical devices and is connected to the battery's negative terminal.