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Re: Brake light replacements? Third brake light?

To: Desmond Mullen <>
Subject: Re: Brake light replacements? Third brake light?
From: Chad Cooper <>
Date: Sun, 17 Sep 2006 08:04:21 -0500
Well I noticed the whites being brighter but  like I said the Autozone 
LEDs I tried were the RED ones, and they were not as robust as the white 
ones from autolumination.  So the difference in number of LEDs in the 
white ones may have made the difference in my case...

Desmond Mullen wrote:

>I think I read that if you use white LEDs in an application that has a red
>lens (like an MGB tail light) then the red lens will cancel out all but the
>red wavelengths coming from the LED (which won't be that much on a white
>LED). They recommend that you use red LEDs with red lenses.
>I did a search and found a number of references. One interesting article is
>"According to Mike Walma, electronics/optics engineer, the LED white light
>is a combination of all wavelengths of light. The red lens acts as a filter,
>blocking all wavelengths except red. This makes the use of a white LED
>behind a red lens very inefficient, with output losses around 50% and up.
>LEDs are very efficient at producing one color (wavelength) of light. LEDs
>producing the full spectrum of white light are not as efficient, and the
>light output not passed through the lens is converted to heat."
>So, it sounds like we've got to use white LEDs.
>'78 MGB
>On 9/16/06 12:00 AM, "Roger Wilt" <> wrote:
>>I agree with idea of brighter brake lights for safety so I ordered and
>>received a pair of replacement bulbs for my MGB 1157's -Matrix II 32 LEDs
>>from and they are putting out less than 1/2 the wattage
>>than my old 1157. Dangerously dim. I'm probably sending them back.unless
>>someone has a great idea of what's up -remember the old 1157's are working
>>fine. I checked, cleaned contact points etc.

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