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1W LED Help.. Answered

I'm new to this site and after what I've seen here very excited to try some of the projects...especially the ones having to do with modifying power tools batteries...but I digress...

I read the write up about the 1W LED's and it was very helpful...my project entails using these LED's in the creation of an integrated tail light for a motorcycle...I was thinking 3 of these lights in red as the running and brake lights...I know they have the potential of being extremely bright...I wanted to run the running lights at normal output, as not to blind anyone, and the brake lights to come on very bright..currently I made a brake light with 5mm and 10mm LED's but looking for something a bit different and brighter...
Here are some pics of my prototype:

So my question is what is the lowest brightness I can go to run constantly and what is the maximum brightness I can go without burning up a my entire tail light?
Also where do I get resistors that can handle these LED's? I wanted to string them together in parallel because since they are tail lights if one blows out I will still have the rest running..



Seeing as your powering it with a battery connected to an alternator , as g moon said the voltage will vary so deffinetly put a regulator in there. As for the brightness I would use a variable resistor to be able to adjust the brightness and a defused lens so that no one is blinded but you still have a bright red light for cars to see you. To difuse a lens simply buy a plastic lens and sand it until its foggy all around and you got yourself a nice bright brake light


10 years ago

Good things to consider because of the variable voltage....and also like the torch idea thought I'd probably have to resolder LED's on because they usually are white...I wanted to used the 1W leds' because of the 120 degree viewable compared to the 20-45 degree on regular 10mm LEDs...


10 years ago

I'd use a regulator circuit, and resistors. Anything with an alternator (car, cycle, etc.) has a variable operating voltage (for 12V vehicles: <9V cranking, >14V charging, ~12V sitting.)

A voltage regulator with plenty of cap filtering will bring it down to 5V or 3.3V. Then you can chose a resistance value that gives you the brightest possible setting, without worrying about peak voltage (add some spike protection, too.)

Why not just buy a LeD torch... With the accurate brightness... Then rip it apart.... Battery housing, LeD's(pre-wired) and switch etc.... That's what i did.... Had to dim mine .... Car's were having to pull over because they couldn't see, behind me... So riping apart a torch was a cheap option.. :)