“Braking News” or “LED Story” – Dave’s Garage

How many of you are worried about over-taxing the electrical system on your antique car?

How many of you are looking for a way to make the rear lights on your car more visible? Recently I was behind a Cadillac with a LED third brake light and conventional incandescent left and right stop/directional lights. I was struck by how much faster the third brake light illuminated as compared to the conventional incandescent tail lights when the driver hit the brake.

I thought about this when our MG TD burned out yet another brake light switch. The replacement brake light switch lasted about 300 miles before it burned out. The replacement switch just can’t handle the amperage of the incandescent stop lights. The MG does not have a relay in the brake light circuit, or any other circuit for that matter. All the switches in the car handle the full amperage of the circuit. Of course this is true for the stop light switch too.

Another problem with the tiny brake lights on the MG is they are dim, and not very visible. I have almost been rear-ended more than once, and I have even had people yell at me that the lights don’t work, because they could not see them in day light.

So, I have decided that with the lower current draw, quicker illumination, longer life, cooler operating temperature, and most importantly, the brighter light it would make sense to replace the standard incandescent bulbs with modern, plug in LED bulbs.
The old bulb is a clear bulb behind a red lens, so it makes since to get a replacement white led bulb right? WRONG! Science has a nasty way of proving conventional wisdom to be wrong.

Here is the reason that you do not want to use white LEDs behind a colored lens or filter:

• Unlike tungsten lights, white LED’s ‘trick’ the eye into seeing white. Most White LED bulbs are made using two wavelengths of light, 460 nanometer Blue and 590 nanometer Amber. They are mixed about 70 percent blue and 30 percent amber. Using white LED’s behind a filter (Red or Amber) will actually result in very little light being visible at all. This is because red and amber LEDs are color specific, they only emit one color. Incandescent bulbs and white LEDs produce all colors, which produces a visible white light.If you put a white LED behind a red filter, all of the colors and the light energy required to produce those colors are filtered out, re-sulting in a much dimmer light.Assuming that you are using a white LED behind an amber or red lens, you will lose (in the case of an amber lens, about 70% of the light generated). It is a very counter productive thing to do.This is why they make white, amber and red plug in replacements for standard 1156 and 1157 bulbs.

  The physics behind this is a bit complex. All you need to remember is to use a white LED with a white lens, a red LED with a red lens, and an amber LED with an amber lens. Simple enough, huh?

  LED lights are another great invention that offers a modern, plug in upgrade to the old car hobby. LED lights are much safer, use a fraction of the electricity, run cooler, shine brighter, light up faster and last much longer than conventional incandescent bulbs. By replacing just the rear bulbs, there should still be enough of a load on the circuit to still cause the flasher unit to operate for the directionals.

  LEDs are Light Emitting Diodes. Diodes only allow electricity to travel in one direction. They are like one way valves for electricity. When ordering replacement bulbs you must specify positive or negative ground, and 6 or 12 volts.

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  Please email all inquiries to: Dave
  or snail mail
  32 Turkey Hill Road
  Richmond VT 05477