Nickel vs. Brass: the Best Tail Light Bulbs?

Whether you drive a BMW, Porsche, Mercedes Benz, Audi, Mini or Volkswagen in Austin, your vehicle utilizes a variety of light bulbs internally and externally for illumination. Although bulbs vary significantly, the intent of this post is to discuss the difference in bulb base materials and their impact on your vehicles connectors, contacts and light assemblies. Most German vehicles bring 12 volt power to the light assembly through a wire harness that terminates within a plastic connector or socket. This socket then mechanically attaches to the light assembly which is most often plastic and incorporates a wiring backing plate or circuit board to branch power out to each bulb within the assembly.

There are two common reasons a bulb fails to illuminate. The first is that the bulb itself has failed internally (broken filament, broken seal, etc.), and the second is distortion in the socket and/or plastic light assembly preventing good conductivity. This distortion is most often a result of heat being generated by the bulb itself. This heat distorts the plastic socket and the plastic light assembly and often will actually melt the plastic around the bulb socket preventing conductivity.  Reducing the amount of heat increases the life of the plastic light assembly and socket.

There are three common base metals that automotive light bulbs use in their construction: nickel, brass and aluminum. These metals are popular in automotive applications due to all three being relatively corrosion resistant. Although all three are corrosion resistant, they conduct electricity and transfer heat differently. Where applicable, German Auto Center recommends nickel base bulbs over brass or aluminum for your BMW, Porsche, Mercedes Benz, Audi, or Volkswagen.  This is due to reduced thermal transfer while maintaining high electrical conductivity ratings.

Nickel (Ni) is a chemical element that is silvery-white in color. Nickel has a slow rate of oxidation and is considered corrosion resistant. Nickel has conductivity properties comparable to brass, while maintaining a lower thermal coefficient (meaning it transfers less heat than brass).

Brass is an alloy comprised of copper and zinc. As this is a composite alloy, properties vary based on the percentage of copper and zinc used in the manufacturing process. Brass has a relatively low melting point and as such is easy to cast and is a popular choice of manufacturers.  Again, although brass (like nickel) is corrosion resistant and has a similar conductivity rating as nickel, brass has a higher thermal coefficient and transfers more heat than nickel.

The third material used is Aluminum (Al). Less popular than nickel and brass, aluminum has a higher conductivity rating, and as a result much higher thermal transfer than either nickel or brass. Another disadvantage of aluminum is the relative soft nature of the material.

German Auto Center recommends the use of nickel replacement bulbs as they provide a lower thermal coefficient and as such produces less damage to the plastic light assembly and socket itself. Follow these simple suggestions and listen to Porsche, Volkswagen, Audi, Mercedes Benz and BMW service experts in Austin. If you have any questions, simply come by and visit Austin German automobile repair experts at German Auto Center and we will be happy to assist you!