What is the brightest red 5 mm LED?

[Cemoi]

I would like to upgrade a couple of bike tail lights, by replacing their 5 mm LEDs with brighter ones.
If I use a white LED (e.g. the Nichia GS which seems to be currently the brightest LED available in the 5 mm form factor), most of the luminous intensity will be filtered by the red plastic cover of my bike lights. I suppose I need to use red LEDs to avoid that, hence my question.

 

[LukeA]

What wavelength are you looking for? Shorter wavelengths are brighter to the human eye, but can look orange.

 

[Cemoi]

What wavelength are you looking for?

I don't know/care. What I want is to get as much light as possible once filtered by the red cover of a cheap bike tail light like e.g. this one or this not-so-cheap one.

 

[gorn]

If it has a red filter then why not put a real bright white LED in it?

 

[Cemoi]

why not put a real bright white LED in it?

Because I read somewhere on CPF that the light produced by the white LEDs has a significant amount of energy in the blue part of the spectrum, which is completely blocked by a red filter.

 

[Jarl]

Completely true. Red filters are a great way to cut the output of an LED down.

 

[Cemoi]

According to this table on Nichia website their brightest red 5 mm LED is the NSPR510CS whose output is 5 cd, whereas a white GS is rated at 30 cd.
What will be brighter when seen through a red filter: a 5 cd red LED, or a 30 cd white LED?

 

[Doh!Nut]

I think that if you are going to fit one into an existing light the higher Vf of the white LED would prevent it working. I have tried putting a white LED in an old rear light (with a clear lens) and it does not work.:thumbsdow

However I have got some 14000 mcd LED from BestHongKong and fitted them in the Catee that you show. This link http://www.myra-simon.com/bike/cateyetail2.html also shows how you can boost the output of the light.
The link shows an early 3 LED version but I used the later 5 led version which worked well.

I also ordered some 25000 mcd LED but have not got round to fitting them yet.

N

 

[crazedmodder]

Why not try using a Lumiled Superflux? Also, red-orange is closest to the original taillight color and it's brighter than the straight red parts. A lot of people prefer the superfluxes.

 

[Cemoi]

I think that if you are going to fit one into an existing light the higher Vf of the white LED would prevent it working. I have tried putting a white LED in an old rear light (with a clear lens) and it does not work.

I thought it would work from the replies I got in this thread.

I also ordered some 25000 mcd LED

Are these Nichia DS? Where did you order them from?

 

[Doh!Nut]

I got the 25000 mcd red ones from BestHongKong, that is they are binned up to 25000 so I guess they are much lower than that (but above 14000mcd)

I had a look at the B&M site, it is not clear wether that light has white LED or red/yellow LED.
If it was a red/yellow I doubt it would run white, but try it, you are unlikely to break it, whichever colour you use there are still worthwhile gains to be had using a better LED.

N

 

[Cemoi]

I got the 25000 mcd red ones from BestHongKong, that is they are binned up to 25000 so I guess they are much lower than that (but above 14000mcd)

So that's much more than the brightest red Nichia.
Which reference is this? I found several 5 mm red LEDs on their website.

I had a look at the B&M site, it is not clear wether that light has white LED or red/yellow LED.

This thread was about another project (no red LED required here): this is a front bike light, whose original two LEDs are an intermediate color between yellow and green.
I have white Nichia GS on order to upgrade these, but now I am worried about the Vf issue you have mentionned.

 

[Cemoi]

Why not try using a Lumiled Superflux?

Thanks for the suggestion, can you please provide a link to a place where these can be ordered?

 

[crazedmodder]

http://www.componentsuperstore.com/...1102010200&ManufacturerName=LUMILEDS+LIGHTING

Just make an account, put in some fake company's name and voila. They have the Amber, Red and Red-Orange superfluxes in varying angles. They're all 70mA though.

The manufacturers website:
http://lumileds.com/products/line.cfm?lineId=4

It's a 4 pin LED, two anodes (positive) and two cathodes (ground).

And http://www.hidplanet.com/forums has a good deal of information and project logs of LED modifications to cars if you need any (only thing is that you have to sign up to see the forums).

 

[Cemoi]

It's a 4 pin LED

Thanks for the links, but as I'm a complete nube at modifying lights and using LEDs, I need LEDs which I can very easily swap with the 5 mm LEDs that are in my bike tail lights (only need to unsolder/solder).

 

[Cemoi]

Which reference is this? I found several 5 mm red LEDs on their website.

I found it here and ordered it, thanks Doh!Nut.