Auto lamps put to the test – only brand lamps give convincing performance
Poor visibility is one of the commonest causes of accidents. So optimal auto lighting is all the more important. And that starts with lamps that work exactly as they are supposed to.
But what many headlight lamps deliver is often not what is promised on the packaging. That was revealed by extensive testing at Karlsruhe University's Lighting Technology Institute. The quality of 100 conventional H7 halogen headlight lamps was tested on the basis of the mandatory approval criteria of the Economic Commission for Europe (ECE). And there should be no lamps on the market in Germany that do not meet those requirements.
What the testers found was that quality lamps lead the field. Only brand lamps received a "good" rating, only quality lamps are safe.
While the brand lamps of German manufacturers surpassed the minimum test requirements with ease, the no-name products in the test performed poorly. The failure rate among non-brand lamps was 81%. The test verdict: "poor".
The results for non-brand lamps at a glance:
- Overall failure rate = 81%
- They are too dim
The weakest vehicle lamps in the test delivered only 60% of the light output prescribed. Among the lamps that produced poor results, products with blue tinted glass designed to imitate the light colour of expensive xenon light performed particularly badly.
- They fail to direct light properly
Beams are too low or too high, too far to the right or left.
- They do not illuminate the road correctly
So the motorist fails to identify hazards and obstacles or sees them too late.
- They dazzle oncoming traffic
A number of inferior lamps produce too much stray light – in some cases, enough to resemble a headlight switched to high beam.
- They consume too much power
Some test candidates exceeded the permitted power consumption in watts. That can result in high heat gain and even damage the headlights.
Test criteria similar to approval criteria
The lighting technologists tested four units of each type, purchased in different parts of Germany. The number of test samples was thus close to the five samples required for an approval certificate. As well as quantity of light – crucial for brightness on the road – and wattage, the testers also looked at the position of the filament and thus the geometry of the lamp, which plays a significant role in defining the quality of headlighting. The finding: 52 of 100 test candidates failed even the geometry test. Together with the lamps producing too little luminous flux, this made for a failure rate of 81%.
Some lamps were found by the testers to be so poor that they ought to be removed from the market. The laboratory has reported the findings to the Federal Motor Transport Authority.
Comprehensive information is provided by trade journalist Fritz Lorek in his pamphlet "Low-quality automotive lamps jeopardize safety“ (only in German).