1. Reliability and service life
The expected service life of LED is 50000 hours, while halogen tungsten lamps have 20000 hours and tungsten incandescent lamps have 3000 hours. Compared to incandescent lamps, LED has a sturdy structure that is not easily affected by vibration, and the brightness of the light output will not significantly decrease during use. The lighting scheme based on multiple LEDs also has the advantage of redundancy, allowing the lighting device to continue to be used even if one LED fails.
Proper use of LEDs (especially by correctly controlling their temperature) can effectively extend the expected lifespan of LEDs. On the contrary, if the temperature is too high, the LED is easily damaged. The application of LED in automotive lighting also involves many legal definition issues. Most countries have a clear definition of brake light or headlight malfunction - lights on or off. But for lamps that use multiple LEDs, it is difficult to accurately define whether the lighting has been damaged. Manufacturers and legislative bodies are defining the usage methods of LEDs.
2. Efficiency/lumens per watt
Compared to standard incandescent lamps, LEDs can generate more light output per unit of electricity consumed. However, compared to halogen lamps, the actual advantage of LED light output is not significant. The latest LEDs have excellent lumen per watt values, but some values are obtained under optimized conditions rather than typically under maximum output conditions. Generally speaking, when the current of the LED increases, the light output does not increase linearly. Therefore, even if the LED outputs x lumens at 0.5A current, it will not output 2x lumens at 1.0A current.
3. Response speed
Taking brake lights and direction indicator tubes as an example, assuming a vehicle speed of 125 kilometers per hour, or 35 meters per second, the hot start time of the incandescent lights is about 250 milliseconds, and the responsive LED can issue a brake warning about 8 meters earlier, effectively avoiding car collisions. The same goes for indicator lights.
4. Directionality
Another key feature is the way LEDs emit light. Unlike incandescent lamps, LEDs only emit light through one surface, which is beneficial for headlight and navigation lighting applications, but may not be suitable for other lighting applications such as cabin lighting.