There are two main types of LED car lights: lens headlights and plug-in headlights;
The effect of lens headlights is better, the light is more concentrated, and the tangent between light and dark is more obvious, but the cost is high;
In-line headlights directly replace halogen lamps with LED lamps on the original reflector bowl. The light pattern is relatively weak, but it is cheap.
1. Lamp beads
Lamp beads are the core part of LED lamps. There are two main types of lamp beads used in car headlights: COB lamp beads and CSP lamp beads. COB lamp beads were used in the earliest lamp holders mentioned earlier. They have high luminous efficiency and are cheap, but they are large in area and inconvenient to increase the power. They are difficult to match with the reflective bowl and the light pattern is relatively diffuse.
CSP lamp beads are the mainstream on the market now. They are smaller in area, closer to the position of the halogen filament, and better matched with the reflective bowl. They are divided into single rows of 3 lamps and double rows of 6 lamps. However, double rows are not necessarily better than single lamps. The high power of the row depends on the size of the wick. A 70mil single row has higher power than a double row of 45mil. The single row is smaller and more suitable for reflective bowls, so the actual effect is
Single row 80mil > Single row 70mil = Double row 55mil > Single row 55mil > Double row 45mil
2. Color temperature
Color temperature is the color of light, and the unit is Kelvin (K). Sunlight at noon on a sunny day is about 5500K white light. The smaller the value, the more yellowish it is, and the larger the value, the more bluish it is. The lower the color temperature, the stronger the penetrating power, and the better the effect in rainy and foggy days. , the higher the color temperature, the higher the visual brightness, and the better the effect on sunny days. 4500K is relatively balanced and is the ideal color temperature. However, the color temperature of LED lights is mostly between 6000-7000K, because white LED itself is made of blue light mixed with yellow phosphor. Lowering the color temperature requires the use of more phosphors, which results in higher costs and lower luminous flux. On the contrary, it is not pleasing to the eye. Currently, I think If you want a 4500K color temperature, you can only find a three-color temperature variable lamp, but the brightness of this kind of lamp is weaker.
3. Power
The parameter that measures the amount of light emitted is lumens (lm), and the unit of power is watts (w). The higher the power, the higher the luminous flux, and the brighter the car lights. Automotive LED headlights are generally 80-100 lumens/watt, and halogen lights are 20-30 lumens/watt. Watt, so LED lights are brighter than halogen lights and require at least 20w.
The actual power of most COB lamp beads on the market is only 15-25w. In addition, it is not well matched with the reflective bowl. In the end, it may not be as bright as a halogen lamp. If the COB lamp bead has a higher power, the area will be very large, and the light will be even brighter. scattered.
The power of CES lamp beads is generally 25-60w, because the heat generated by greater power will cause light decay and even damage the LED wick, and the light efficiency will be greatly reduced, which is very uneconomical.
Power recommendation: reflective bowl 25-40w, original car lens 40-55w.
4. Heat dissipation
The heat generated by LED car lights is actually not large, but it is not heat-resistant. The current technology has a junction temperature of about 120-150°C, so the higher the power, the more efficient heat dissipation is required. Otherwise, the light will be attenuated or even damaged, and the cost of the heat dissipation components will be even Higher than lamp beads.
Most of the volume of LED car lights are heat-dissipating aluminum parts. The temperature of the light source is transmitted to the aluminum parts through the substrate, and then to the tail end for further heat dissipation using fans or heat sinks. For high-power ones, a liquid tube is required next to the substrate. Speed up thermal conductivity efficiency.
Generally, the maximum load capacity of the heat sink is less than 30W, the fan is 40W, and the liquid pipe + fan is more than 50W. Anyone who claims more than 50W without a liquid pipe is a rogue.
5. Driver
The function of the driver is to stabilize the current and create a constant current environment so that the lights will not flicker. A driver with EMC anti-interference can also isolate the interference of the car lights on other equipment, such as driving computers, audio, navigation, and interior lights. There are both external and integrated drivers. Integrated drivers are smaller in size and have higher installation efficiency, but they will increase the difficulty of heat dissipation. External drivers cannot be installed in some models with small lampshade space.
The vehicle's driving computer will generally check whether the lamp current is normal. If it does not pass, the fault light will light up on the instrument panel. Most cars can pass if they have EMC, and some models require an additional decoder to pass.
6. Voltage
The voltage of cars is generally 12V, and the voltage of trucks is generally 24V. When buying, you need to choose the corresponding voltage model. Nowadays, most LED car lights are wide voltages that support multiple voltages.
However, the voltage of some trucks will fluctuate greatly when the accelerator is stepped on, causing the lights to flicker. This kind of trucks must choose a 10-80V ultra-wide voltage model to solve the problem.
7. Model
This corresponds to the halogen lamp interface and plug model. If you choose the same model as the original car, you can replace the original car bulb without damage. The parameters of different models of the same model are the same. The mainstream interface models are: H1, H3, H4, H7, H11 (8/9), 9005 (9006), and 9012. The H4 has integrated high and low beams. It uses twice as many lamp beads as the others. The price is generally more expensive than other models. Some models require special buckles.
