Will the car battery drain if the car is only powered on but not started?
2 Answers
Keeping the car powered on without starting it will drain the battery. The car battery provides power to the starter and ignition system, supplies stable DC power to the car's electrical appliances, and ensures that the car's electronic circuits and DC lighting system can function normally even when the car is parked. Working principle: During charging, electrical energy is converted into chemical energy, and during discharging, chemical energy is converted back into electrical energy. When the battery discharges, metallic lead acts as the negative electrode, undergoing oxidation and converting into lead sulfate; lead dioxide acts as the positive electrode, undergoing reduction and converting into lead sulfate. Battery maintenance: Avoid parking the car in an open parking lot for extended periods. If the car is to be parked for a long time, the battery must be removed and taken away to prevent it from freezing and getting damaged. The car battery should be charged regularly. If left unused for a long time, the battery will gradually discharge on its own until it becomes unusable. Therefore, the car should be started periodically to recharge the battery.
I often modify cars and know that just powering on without ignition will definitely drain the battery. When the ignition is in the ACC or ON position, small electrical appliances like the radio, headlights, and fans are all running, relying entirely on the battery. Although the battery can last for a while, prolonged use will deplete it, and if it’s completely dead, the car won’t start, which is really annoying. Once, I ran the air conditioner for half an hour while waiting in a parking lot, and the battery level dropped significantly—I had to get a jump start later. I recommend not exceeding 20 minutes or carrying a portable power bank as a backup. Be especially careful in winter, as battery performance declines faster. Regularly check the battery voltage with a multimeter to avoid pushing an aging battery too hard. Batteries aren’t expensive, but dealing with them can be a real hassle.
