How to Change Color Rear Light From Red to Yellow

Red or White LED bulb behind a Red Lens? (with video demonstration)

Welcome to the next instalment of ABD TV where we aim to answer all of those burning questions, clear up the confusion and leave you brimming with knowledge.

Red or White LED Bulb?

In this episode we're tackling a common question we get asked: Is a coloured LED bulb or a white LED bulb is better behind a coloured lens? This is a common issue with applications such as a brake light or indicator.

For some cars, the actual front or rear light units have clear lenses and the colour of the light is determined by the bulb. For example this amber 581 bulb for the indicators on this headlight unit:

However for others the colour is determined by the lens of the unit itself. As is the case on this rear cluster.

In these cases, the bulb behind the lens would be a standard white filament bulb such as this 382 bayonet bulb.

But what happens when you're upgrading to an LED bulb?

The common sense reaction would be to swap like for like. If you have a clear lens with a coloured filament bulb, use a coloured LED. If you have a white/clear filament bulb behind a coloured lens, use a white LED. But is that actually the right thing to do?

The Test – Red Vs White

Obviously if you have clear lenses, you will have to use a coloured LED bulb so we're not going to test out anything there. That's just common sense. But let's have a look at the difference between a white LED and a red LED behind a red lens.

The Brake Light

For this test, we are using the red and white versions of the Twenty20 Cree Canbus LEDs for brake lights. They are identical except for the colour so there's no issue with mis-matching bulbs. The results you see are simply due to the difference of the colour.

As you can see from the pic, the red LED bulb is producing a much more intense and bright light. What is not so clear on the image is the difference in colour.

The white LED is producing a washed out red light, a kind of "light red". It's not as far as pink, although we have had some people report that to be the case, but it's certainly a lesser red than you'd expect.

The red LED is producing a very intense and pure red light. Much better for this brake light application.

Those Pesky Misleading Lumens

Another important thing to note is that the white LED is rated at 750 lumens. The red LED bulb is rated at only 350 lumens. A lot of sellers out there use the lumen number as a marketing tool. Hey come buy this, it's the brightest thing in the World and a million lumens! OK a bit of an exaggeration but you get the idea.

It's not about the total lumen number, it's about how usable that light is for the application that it's being used for! You can see another example of this in our LED Headlight blog.

So let's take a look at this from a different angle:

The Light Projection

Once again it's clear to see which one is performing the best. The amount of red light hitting the board from the red LED bulb is far greater than the light from the white LED bulb.

So there you have it. When upgrading to LED, go with the colour that the application is for regardless of whether your standard bulb is white or coloured. This will give you the best and brightest results.

If you have any questions on this, feel free to ask them in the comments below.

Also if you have any other general product questions you'd like to see us cover in a future ABD TV episode, please send them in either via our social media accounts or via email.

UPDATE: A reader of ours suggested that amber lensed indicators, it is better to use the white LEDs as they come through brighter. We thought we'd put it to the test. Find out here if you should use Amber LEDs or White LEDs for indicators behind an orange lens –>

How to Change Color Rear Light From Red to Yellow

Source: https://www.autobulbsdirect.co.uk/blog/red-or-white-led-bulb-behind-a-red-lens/

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