|Q1: ||Are these setups street legal?|
These setups have not been certified in any way and are intended to be for "show use only." Use them on the street at your own discretion.
|Q2: ||I can get LED bulbs at the local auto parts store - they're readily available and are much cheaper. Why are these better?|
Let's compare the common retrofit LED bulbs with my LED setups:
- To increase perceived brightness, the common retrofit LED bulbs use LEDs with small beam angles - around 30°. The LEDs I use have a 90° beam angle which provides much better coverage, and the total light output is much greater overall.
- The common retrofit bulbs arrange the LEDs within a relatively small circle, leading to a "spot" of light in the lens. The configurations I've developed fill nearly the entire lens area with light.
- Many cars have low voltage at the bulbs and/or voltage differences side-to-side or even within a housing; for example, my '86 535i has only ~11 volts at the brake light bulbs even with the alternator putting out over 13 volts. The common retrofit LED bulbs use resistors for current regulation, which means the light output will vary with input voltage. My setups use voltage regulators or current drivers to produce consistent current to the LEDs from 9 volts to 30+ volts, which means that my setups will produce consistent light output from vehicle to vehicle and between the lights in the vehicle.
|Q3: ||Does replacing incandescent bulbs with LEDs affect the electrical system?|
Yes. The reduced current of the LEDs has a number of effects:
- If the vehicle has a bulb failure detection system, erroneous bulb failure indications are likely. On mid-'80s BMWs, this can be fixed by bypassing the check control reed switches with jumper wires; depending on the setup, I either supply the jumper wire or the wiring harness for the setup incorporates the jumper.
- On mid-'80s BMWs, if all the brake light bulbs are replaced with LEDs, the cruise control will no longer function; this is because the cruise control uses the bulbs as the drain to ground, shutting the cruise control off during brake application or if all the bulbs are burned out. This can be avoided by keeping at least one incandescent bulb (i.e. the third brake light) in the system, adding a drain resistor to the circuit, adding extra pin switches on the pedal cluster, or adding a relay to the circuit.
- The turn signals will either not flash or will exhibit "bulb out" behavior. There are aftermarket turn signal flashers designed for LEDs that will correct this.
|Q4: ||Instead of using red LEDs for the brake lights and amber LEDs for the turn signals, why don't you just use white LEDs? The lens will make the light the proper color.|
The LEDs I use are specifically designed for automotive use and do not come in white - there is a good reason for this. A colored lens is essentially a filter which prevents all light of other colors from passing through. What happens to this light? It is wasted in the form of heat. That means that a corresponding amount of input power is wasted as well. For a given amount of light output for a particular color, colored LEDs are much more efficient than an incandescent bulb putting out full-spectrum light, most of which will be wasted; similarly, white LEDs would have most of their light wasted as well. This is why there are no white LEDs designed for automotive signaling.
|Q5: ||Can you make LED setups for other vehicles?|
Yes! I will need at least one "guinea pig" housing for use in developing the setup - it will get mutilated! Once I have tinkered with the housing, I will be able to give you an estimate for the cost of the prototype.