What are the effects of leaving the car air conditioner on overnight with the engine off?
2 Answers
Vehicle may not start the next day. There are two key points to note: 1. Not unplugging external devices from the power outlet after turning off the engine: For convenience, many external devices such as GPS, dash cams, and air purifiers are connected to the power outlet. Some car models' power outlets remain energized even when the engine is off. If external devices are not unplugged, they will drain the battery, causing damage to it; 2. Leaving the headlights on after turning off the engine: If the car suddenly stalls, there's a possibility of forgetting to turn off the headlights. It's important to note that the parking lights will remain on until the battery is depleted.
I've experienced this situation before - leaving the car AC on overnight after turning off the engine is really not a good idea. The main problem is that it completely drains the battery. Since the engine isn't running, while the compressor doesn't work, the fan keeps blowing all night, consuming all the electricity. The next morning, I couldn't start the car and had to call for a tow truck or ask someone for a jump start - both costly and time-consuming. What's worse, deep discharging the battery like this several times can ruin it, reducing its lifespan from years to just months. Replacing a new battery costs several hundred dollars. Similar mistakes like leaving headlights on overnight are equally dangerous. I'm also concerned about prolonged electrical circuit operation causing overheating - any sparks could potentially create a fire hazard, especially in older vehicles. That's why I've developed the habit of turning off all electrical devices before shutting down the engine. When parked, choosing a shady spot or slightly opening windows for ventilation is sufficient. Safety first - it's not worth taking this risk.
