Bartosz Tomeczko varia


Chinese H7 halogen bulbs

Why is it NOT wise to order safety-critical thingies from Chinese shops? Check it out.

Recently I've been reviewing my car's technical condition and (both with the guy from the diagnostic station) we found out that my headlight isn't working properly. Actually the lights were completely out of focus. I have checked the position and locking of the blub inside the fixture but it was mounted correctly. And in this very moment I recalled that few months before I have installed some cheap Chinese H7 halogen light bulbs instead of buying (more expensive) Bosch/Osram/whatever from European distribution (or especially from the gas station). Yes - this was the correct clue.

Normally this Chinese H7 light bulb looks normally - like H7 bulb - normal 12V/55W:

 Chinese H7 bulb

However comparing the bulb with the H7 manufactured by Bosch we can see this:

Comparison between Bosch (left) and Chinese (right) bulbs

This shows that the Chinese bulb is circa 7-8mm shorter that the one from Bosch. How does it influence the lighting of the car? It influences it greatly! Just take a look at this (simplified) schematic how light beams are formed on the mirror of the headlight (with both "normal" and "too-short" light bulb):