Can a car run after removing the battery when it is started?
2 Answers
After starting the car, removing the battery will prevent it from running. Reasons why removing the battery prevents the car from running: The car battery is not only responsible for starting the engine but also provides power to other electrical devices in the car. Once removed, many electrical components such as the dashboard, headlights, and horn will stop functioning, and the car will not be able to move. Principle of the car battery: It has a certain self-discharge rate, meaning it naturally loses some charge even when no electrical components are connected. During long-term parking, if the car has power-consuming devices like anti-theft alarms or dashcams, the battery consumption will be even greater, potentially leading to a dead battery. Therefore, it is recommended to disconnect the negative terminal of the battery to avoid severe battery drain. However, removing the negative terminal can also have certain consequences.
I've been repairing cars for over a decade, and this operation should never be attempted. Disconnecting the battery cables while the engine is running may seem like the alternator can still function, but it's extremely dangerous. The alternator requires the battery as a voltage stabilizer. Removing the battery causes the voltage to instantly surge above 15 volts, which can easily burn out expensive electronic components like the engine control unit and headlight modules, costing thousands. Moreover, the steering wheel will suddenly become heavier, brake assist will gradually disappear, and the car may lose control at slightly higher speeds. Last month, a car owner tried this on a highway and instantly burned out the ABS pump, costing over 7,000 yuan in repairs. To properly check the alternator's condition, use a voltmeter to measure the voltage across the battery terminals. After starting, the voltage should be between 13.7 and 14.3 volts for normal operation.
