Bright Tail Light

Do you know what LEDs can be used for making a very bright red (not amber/orange) tail light?

Any red power LED will do it. For instance you may want to look at Cree MC-E or XP-E LEDs, as those are models that do come in red. You may wish to use several.

carrot said:

Any red power LED will do it. For instance you may want to look at Cree MC-E or XP-E LEDs, as those are models that do come in red. You may wish to use several.

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Indeed. You may want to look at at least 5 watts total. I have some 3W "drop-in" 1157 units that aren't quite as bright as I'd like.

Use a lot of 5mm high brithnest leds, buy in ebay, connect groups of 4 leds in serie with a 180ohm resistors and this groups in parallel, install them in a universal PCB, then use a 220ohm 5 watts with a diode for the tail light, is easy to build than high power Leds, let me know if you need more help about it...

Changchung said:

Use a lot of 5mm high brithnest leds, buy in ebay, connect groups of 4 leds in serie with a 180ohm resistors and this groups in parallel, install them in a universal PCB, then use a 220ohm 5 watts with a diode for the tail light, is easy to build than high power Leds, let me know if you need more help about it...

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just wondering how this compares to a few cree's. i might be doing this sometime soon.

subscribed for reference

Maybe not that bright, but is easy to build and lasts a long time without problems...

I do mines as well with some piranha 120 degrees leds for the tail light funtion and 5mm 20 degrees for the break... The results are great...




SFMI4UT

Is this for a motor vehicle/motorcycle? Or just a bicycle?

If it's for a motor vehicle or motorcycle, you cannot build functionally compliant taillamps yourself. The 1157 "drop-ins", whether homemade or made in some factory somewhere (and despite being sold over the internet and in auto parts stores alike) also result in your taillamps being noncompliant.

for my application, bike trailer. i want them to be bright enough for people to think it might be a vehicle. i'll still be using 12v systems (already have the stuff), so automotive applications suite my needs

thanks for all the info, guys. really helpful. i'm not new to forums, high-brightness led's, or electronics. i'm just new to this forum and colored led's. also, keeping up-to-date is nice.

irab88 said:

for my application, bike trailer.

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I could be wrong, but the lighting equipment for the trailer must still conform to FMVSS 108 requirements (it appears that if it's for commercial use, it does).

You'd be better off getting a new trailer light kit rather than trying to cram stuff into existing hardware that won't work correctly.

A few samples of what's out there are here.

i want them to be bright enough for people to think it might be a vehicle.

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You'd rather them work in such a way that people identify it correctly as a trailer, so that there is no ambiguity or uncertainty of the message the lamps are conveying.

On the subject of 'ambiguity' I guess we should clarify what sort of "bike trailer" it is.

Is it attached to a) a car or pickup, b) a bicycle, or c) a motorcycle ?

I pictured a trailer attached to a car or pickup, and carrying a motorcycle.

edit: misconception as to what "bike trailer" referred to. see next post.

Alaric Darconville said:

I could be wrong, but the lighting equipment for the trailer must still conform to FMVSS 108 requirements (it appears that if it's for commercial use, it does).

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it is not for commercial use. the laws for my area permit the use of a red steady tail light, visible to 500+ feet.

Alaric Darconville said:

You'd be better off getting a new trailer light kit rather than trying to cram stuff into existing hardware that won't work correctly.

A few samples of what's out there are here.

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thanks, but i can spend all day browsing stuff online to bolt to the trailer. that's not the point. the point is to make it myself, make it fit where it needs to go, and make it aesthetically appealing. i'm only asking for the comparison of brightness here.

Alaric Darconville said:

You'd rather them work in such a way that people identify it correctly as a trailer, so that there is no ambiguity or uncertainty of the message the lamps are conveying.

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the message i want to convey is avoidance. i don't care what vehicle they think it is. as long as they notice me and don't hit me, all is good. (case-and-point: why would they make 2000-lumen bike lights if people think it's an oncoming motorcycle?)

my intent is not to anger or annoy, but instead to make it clear of what i'm asking. if you would rather i start another thread, let me know.

Alaric Darconville said:

On the subject of 'ambiguity' I guess we should clarify what sort of "bike trailer" it is.

Is it attached to a) a car or pickup, b) a bicycle, or c) a motorcycle ?

I pictured a trailer attached to a car or pickup, and carrying a motorcycle.

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my mistake. the trailer will be towed behind a bicycle.

also, i am not the op. i had a similar question relating to the op's, and didn't want to create one-more-thread

irab88 said:

my intent is ... to make it clear of what i'm asking.

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Then clarify: Is this a trailer to be towed by a bicycle?

If so, then you certainly CAN do a homemade light, but again, I caution against making a light in such a way that it makes it more of a danger to you and others due to being overpoweringly bright. It can, and does, happen. When people assume a particular vehicle is motorized, they assume that it is moving faster, or CAN move faster.

irab88 said:

my mistake. the trailer will be towed behind a bicycle.

also, i am not the op. i had a similar question relating to the op's, and didn't want to create one-more-thread

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Since this thread has been "resurrected" and such, perhaps going to the "Bicycle" subforum and creating your own new thread would be best, anyway. Then you'll get to be the OP, and there will be no ambiguity. You might even find good ideas just looking in the existing threads.

yes, one of these (not the same one, but the same concept)

and i fully understand what you mean by "being overpoweringly bright." that's not my intent. my intent is a broad, wide-angle pattern that will be noticed, not blinding.

after further research with cpf and other sources, i have come to the conclusion that an array of 5mm's will do the trick just fine

Sorry, double post...

I bought LEDs for my upper stop light and just plugged them in. They are made/sold for that purpose. They appear brighter than the original incandescent bulbs. If you are going to use turn signals/running lights you may find the OEM flasher won't work because the LEDs don't use enough electricity to activate them. Special flashers and bulbs are available for such use. They can be tricky and frustrating to install, though.

HotWire said:

I bought LEDs for my upper stop light and just plugged them in. They are made/sold for that purpose.

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And are illegal.

They appear brighter than the original incandescent bulbs.

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The human eye and brain are easily fooled. In the chance that they ARE brighter, they may be too bright in some areas, leading to excessive glare.

If you are going to use turn signals/running lights you may find the OEM flasher won't work because the LEDs don't use enough electricity to activate them. Special flashers and bulbs are available for such use. They can be tricky and frustrating to install, though.

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But you can avoid all the hassle (and legal issues) by not replacing the filament bulbs with LED 'drop-ins'.