The nomenclature of spare parts and consumables, which the car owner purchases independently, is steadily declining: even a specially trained person pours gasoline at gas stations. And only a few positions on the shelves confidently hold the defense. A typical example is car lamps. It would seem that the life of bulbs is not so difficult compared to, say, spark plugs. However, the headlights suddenly go out much more often than we would like. At the same time, the vast majority of bulb manufacturers do not indicate their life, preferring indefinite “+ 50%” or immodest “three times”.
By the way, the stronger the declared luminous flux, the lower the lamp life, but this is also not customary to spread about. Unofficial information obtained from one of the largest lamp cases of the manufacturer says that an ordinary lamp should shine for about 500 hours, and various kinds of “improved” ones should be two to three times less. But in fact? In short, we decided to conduct our reliability tests.
HOW TO CLOSE THE BLACKOUT?
The editor has neither the ability nor the desire to drive light bulbs for 500 hours. But he is not forbidden to recall the basics of electrical engineering, according to which an increase in the supply voltage of an electric lamp is extremely negatively reflected in its resource. The addiction is very cool: minus the fourteenth degree!
For example, the increment of the supply voltage by only 10% comes with an almost four-fold decrease in the resource. (By the way, is it possible to check the voltage in the electrical system if you are tired of changing the bulbs?) The second evil enemy of the bulbs is vibration. Headlights on bumps go out much more often than when driving on smooth asphalt (we, unfortunately, did not remember the formula linking the depth of the pothole to the lamp life).
To take into account both factors, we built a test bench with a powerful adjustable power source and a no less powerful vibrator - a kind of great analogue of a vibrating alert from a cell phone. In this overstressed mode, accelerated tests should have taken only a few days. It remained to stick a dozen brand new H7 bulbs into the jacks of the stand.
Note that we tried to purchase both ordinary lamps and “improved” ones from the same company. There were four such pairs, the company they made four more singles. Well, turn on the light …
YES WILL BE LIGHT
Turning on the light, by the way, is very difficult … Twelve light bulbs eat about 60 A, the wires melt, and this whole farm shakes and buzzes merrily! But interesting. First, crawl smoothly from zero: you need to make sure that all the lamps are working and there are no hidden defects. We reach 14.7 V and in this mode we drive the light bulbs for a couple of hours. So far, everything is in order, but the extreme has not yet begun. Smoothly go higher … Stop!
"Chandelier" fades a little: the first loser leaves the race at a voltage of 16.5 V. From this moment we add no more than 0.5 V, keeping the lamps at each line for four hours. On the voltmeter 17.0 V - ten participants remain. 17.5 V - four lamps still on! 18.0 V - the top three are determined.
Finally, the exorbitant 18.5 V complete the test: the first is the Ring R477, followed by the "long-playing" HELLA Long Life. And finally, it gets dark in the eyes: OSRAM Ultra Life finally removes the load from the power source. The champion stayed on our electric rack for about 20 hours. In terms of normal operation, this …
However, no manufacturer, of course, counts his bulb under one and a half overvoltage. Empirical formulas work correctly only with very small deviations from the nominal voltage. In general, any extrapolation is probabilistic.
The scheme opens in full size on a mouse click:
BURNED AT WORK
It is curious that the first two places in our extreme were taken by products with increased declared service life. By the way, lamps for HELLA, according to our information, are doing the same OSRAM, and therefore - double congratulations to the company. Note that visually the spiral of the winning lamp differed from the others in a slightly longer length. This time we did not check the light distribution, since the task was completely different. However, we can repeat our recommendations: we are for products of reputable brands. The likelihood that they will shine correctly and for a long time is still higher.
BTW, ABOUT RESOURCE
- Most often, the bulbs burn out at the moment of switching on: a cold thread has a low resistance and generates a large initial current. Therefore, try not to switch the lights back and forth without the need. Moreover, the dipped beam must be turned on constantly.
- Noticing that when the engine is turned off, the brightness of the lamps decreases markedly, check the voltage in the electrical system. If it is very high (more than 14.5 V), not only the bulbs, but also the battery will quickly fail.
- Do not buy any LED crafts for the head optics, no matter how sweet the seller sings about them! Real LED headlights for Audi R8 cost tens of thousands of dollars, and universal semiconductor substitutes for high-power lamps today simply do not exist. Weak LEDs pushed into the body of a standard lamp cannot shine. Another thing is the daytime running lights: there LEDs perform their function with dignity.