Having studied various correspondence on automotive-related forums, we can conclude that a huge part of motorists encounters the problem of flickering LED bulbs in a car. As a rule, these are motorists who try to improve the interior lighting with their own hands, to modernize marker or lighting headlights.
The chaotic flickering with subsequent failure of an LED bulb annoys the driver. A question arises in his head: “Why this happened?” To deal with similar reasons and find the answer, you need to understand how the LEDs work.
Correct LED activation
The most important LED parameter is the rated current consumption, that is, the current at which the manufacturer guarantees optimal light output during the declared life of the product. Ideally, the function of the current limiter should perform by a current stabilizer built into the lighting light bulb. However, often, this very stabilizer is not there. In large light bulbs, you can still fix the situation. And what about low-power small-sized LED bulbs, which often put in the sidelights, the dashboard, or various small-sized light bulbs in the car interior? The case of these light bulbs is too small even to install a primitive current stabilizer. To solve this problem, special remote stabilizers of the bulb have developed, but for various reasons, most motorists, for some reason, bypass such products.
In a car, LED bulbs powered by a battery, the output voltage of which ranges from 11.5 to 14.5V.
Most motorists connect a 921 LED bulb to the machine’s power supply through a single current-limiting element – a resistor. A resistor is a linear element of an electric circuit, which means that the magnitude of the current flowing through it depends on the applied voltage. Therefore, increasing the voltage on the battery leads to an increase in current through the LEDs. The LED, in the signal, is a nonlinear element, and even a small voltage jump leads to a significant increase in the current through the crystal.
Excessive current through the LED leads to a violation of the temperature regime of the crystal and its strapping. From overheating, an unstable region appears in the junction, which does not pass current continuously, but with a certain frequency. This reason is the main reason for flickering. In some cases, this phenomenon is fleeting, and a light-emitting LED quickly fails. In others, this stroboscopic effect can last quite a while.
Reasons for blinking
If connected incorrectly, the flickering effect begins to manifest itself after a few months of using the LED bulb. And the reason for this phenomenon is not only the lack of current stabilization. Raising the temperature of the crystal above 85 ° C causes him irreparable harm. A good example is the numerous complaints of drivers in whom LED bulbs installed near ordinary headlights. The filament greatly warms the surrounding space, and sometimes even melt the plastic casing of the LED bulb. It is worth noting that in winter, such symptoms may not occur since cold weather contributes to cooling. But in the summer heat, the temperature inside the headlight will easily exceed the critical mark of 100 ° C. And then not branded LED bulbs, nor expensive stabilizers will help. The second possible reason for flickering is the use of LED bulbs in cars with an integrated low-quality stabilizer. The built-in stabilizer in such bulbs does not limit the current at the proper level. Measuring the parameters of cheap Chinese-made LED bulbs shows a smooth increase in current (and brightness) after switching on to a value higher than the nominal one. In such a dishonest way, manufacturers advertise the high light output of their product without worrying about short service life.
We will consider the third reason for the unpleasant flickering on the example of LEDs intended for installation in dimensions and inside the car. They do not require maximum light output, which means that you can connect them through a conventional resistor. Only you need to calculate it not for 12V, but 14.5V, and also find out from the directory the current for the type of LED used.
Often when tuning a car, 1157 led bulbs designed for 12V voltage are used. When you connect them directly to the battery, you will inevitably have to witness a gradual loss of brightness, flicker with the final burnout of the product after some time. To avoid an unpleasant situation with LED strips, at least an additional resistor designed for a voltage of 14.5V will help.
So that the flickering of LED bulbs in a car is not an unpleasant surprise, two simple rules must observe:
- Do not place them near very hot headlights; Do not operate LED bulbs without a properly stabilized stabilizer.
- As a current limiter, you can use an inexpensive LED controller with suitable output current and power. Due to its small size and hermetic housing, such a light bulb will be more effective than a resistor.