How long can the hazard lights last after the engine is turned off?
2 Answers
If it is a new car with a relatively new and fully charged battery, the hazard lights can generally last for more than 10 hours when the engine is turned off. However, if the vehicle is old and the battery performance is already poor, the duration of the hazard lights after turning off the engine will be halved. Here is additional information: 1. Introduction to hazard warning lights: Hazard warning lights, commonly known as car hazard lights or double flashing lights, are functional lights used to alert other vehicles in case of emergencies. Additionally, if parking on the roadside, it is necessary to turn on the hazard lights to avoid rear-end collisions. As lights, hazard lights directly consume the battery power after the engine is turned off, but their power consumption is relatively low. 2. Duration of hazard lights: Taking a typical household car battery capacity of 50-60Ah as an example, when the hazard lights are turned on, all six turn signal lights (front, side, and rear) will flash. Depending on the vehicle, each turn signal light is approximately 6-10 watts, with LED turn signals consuming even less. For a 12V 60Ah battery and a single turn signal light of 8W, theoretically, a fully charged car battery can last: 12*60÷(6*8)=15 hours.
Having driven for many years and researched this issue, I've found that how long hazard lights can last after the engine is turned off mainly depends on the car battery's capacity and health condition. A new car battery typically has around 45-70 ampere-hours, with each hazard light bulb consuming about 10-15 watts, totaling approximately 25-30 watts in power consumption. Theoretically, this allows usage for 6-10 hours. However, in reality, older batteries discharge faster, and in low temperatures or cold weather, the duration can be halved, possibly lasting only 2-4 hours. LED lights are more energy-efficient and can extend the duration by several hours, for example, lasting 8-12 hours without issue. If there's an anti-theft system or the radio is in standby mode, it will further accelerate battery depletion. I recommend regularly checking the battery voltage; if a new battery drops below 12.4V, it should be serviced. Avoid leaving hazard lights on for more than one or two hours when parked to prevent the inconvenience of being unable to start the car when needed.
