LED Lighting

<div class='quotetop'>QUOTE(darelldd @ Jun 22 2006, 12:24 AM) [snapback]275085[/snapback]</div>

This is all good information. I was going to do some research on the issue and start to play around with designing a LED solution for the fog lights as a side project.

True - the barrier for a solution here is cost. Anything I design, develop is going to be incredibly more expensive than something that is mass produced, after all, it would be a one-of-a-kind item.

I appreciate your response on this - and I am also considering ordering a collection of interior LED lights you designed. I will send you an email on that.

 

<div class='quotetop'>QUOTE(darelldd @ Jun 21 2006, 09:24 PM) [snapback]275085[/snapback]</div>

That's true. I've seen an LED replacement for the mini Mag Light, which replaces the reflector as well. I suppose that's why we don't see any for the larger Mag Lights as the fixture in that is movable.

 

<div class='quotetop'>QUOTE(aaf709 @ Jun 22 2006, 05:50 PM) [snapback]275461[/snapback]</div>

I have seen Mag Light replacement LED's before. They were not all that great, but it did work.

http://store.advancedmart.com/20ledlirebuf.html

http://us.st11.yimg.com/us.st.yimg.com/I/y...35_1899_2643924

I would consider packing more LED's into a circle with some LED's on the reverse side hitting a reflector to produce more light towards the sides. Taking from the design in the picture, it is quite possible to create two sets of LED's on 3 PCB's to allow for a greater spread of light.

 

You don't need more LEDs just BETTER LED's.

http://flashlight-forums.com/index.php?topic=2841.0

http://flashlight-forums.com/index.php?topic=1919.0

http://www.ledbeam.com/

 

<div class='quotetop'>QUOTE(benighted @ Jun 22 2006, 06:34 PM) [snapback]275490[/snapback]</div>

Interesting, I was reading up on the 3-Watt Luxeon III emitter, which apparently can produce 65-80 Lumens of light intensity which can reach up to 250'!

Thinking about 4 of them to replace my current fog light, so I will start there. Thanks for the tip benighted!

 

<div class='quotetop'>QUOTE(londo-cat @ Jun 22 2006, 04:38 PM) [snapback]275527[/snapback]</div>

Warning... warning... You can get all kinds of light out of Luxeon stars, but you still have the physical issues to contend with. The big one being heat in a situation of "constant on." A flashlight is often used for minutes at a time. A fog light can be used for many hours at a time, and waste heat will be a big issue if you plan to dirve a Lux3 at anything near 80 lumens. The Lux3 product IS a great choice for high-output applications. I now use them interchangeably with Lux1's for my dome fixtures (all driven at 350mA, and all having almost identical output).

As for "reach" you can send a VERY small number of lumens well past 250' if you have a proper reflector. It will be an insanely narrow beam, and of course totally impractical for a fog lamp.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Jun 26 2006, 11:27 PM) [snapback]277253[/snapback]</div>

do not know. I hope not. You can make projector lenses in any fashion you want. The beam can be modified to suit the purpose. Low-beam projectors are flat-topped with a wide splash underneath, for example.

 

<div class='quotetop'>QUOTE(tcrowson @ Mar 1 2006, 02:30 PM) [snapback]218670[/snapback]</div>

Why didn't you replace the turn signal flasher? Is it easier and/or cheaper to go with added resistive loads?

<div class='quotetop'>QUOTE(darelldd @ Feb 23 2006, 10:03 PM) [snapback]215702[/snapback]</div>

I'm about to replace the brake light bulbs with LEDs and wonder whether it's ecomical and practical to add resistive loads or replacing flashers (LEDs compatible)? Your insights are greatly appreciated.

 

<div class='quotetop'>QUOTE(fiberhwy @ Jul 21 2006, 05:45 PM) [snapback]290233[/snapback]</div>

I'm not really sure what you're after here... If you replace just the brake light bulbs, you won't need an extra resistive load (assuming you use LEDs that are already resistored for 12V as all commercial units would be). If you can find an LED replacement that is bright enough to replace the existing brake lights AND fit through that tiny hole, I'd love to hear about them! Remember that this is a safety issue, so the cheap "resistor only" LED solution for this is not recommended!

Aloha,

 

For some reason the reply page isn't working for me (text box doesn't show up) so quotes won't work. I see you are on the same subject that I hijacked your sales thread with (sorry). I'm going to start working on something that will fit in that hole this winter sometime.

Aside from a few ideas I have I think a resistored solution might work for such a tight space, after all it will still be better than incand because those blow out eventually anyways, right? I resistored two 1 watt batwing emitters in series onto a penny heatsink and got it to fit in the rear dome lite where a regulator board wouldn't, its not as bright as the regulated modules but it works.

 

<div class='quotetop'>QUOTE(benighted @ Aug 27 2006, 09:27 PM) [snapback]310417[/snapback]</div>

Unfortunately, so will a resistored LED solution. The reason for regulation is to protect the LED from spikes that happen regularly (but of a pun there!) in all vehicles. I wouldn't trust a resistored LED solution for a safety item like brakes, signals or tail lights. A regulated solution gives you consistent brightness, and full protection of the emitters.

 

What I'd like to see for the dome light LED is a solution that acts like a resistored installation when dimming occurs, but has peak protection like a regulated device. You know anyone who'd like to design such a beastie for me??

 

Two questions from someone who loves LEDs but doesn't understand them, I guess.

First Cadilacs, Acuras, and Infinities have LED tail lights and stop lights. They work at two different intensity levels. So do most of the busses and trucks I see around here where LED's are used for tail lights, stop lights and turn indicators and side marker lights. That seems to go against what so many are saying here about automotive uses of LEDs. Please explain.

Secondly, a poster said that he was going to install LED brake lights. Don't HSD Prii have LED brake lights? Or are we talking about two different technologies here?

(Boy, do I miss the spel chek!)

 

<div class='quotetop'>QUOTE(darelldd @ Aug 27 2006, 11:31 PM) [snapback]310420[/snapback]</div>

Darell, obviously you know more about LEDs than I do. A few posts back (and a couple months) you were saying if you replace a standard headlight with an LED you'd have to consider the waste heat. I thought LEDs were supposed to be so much more efficient than other kinds of light bulbs. And of course, being more efficient means less electricity is wasted as heat. Even though a replacement bulb may not be shaped exactly the same or put the heat in the same places, it should still be cool enough not to be a problem, given its lower wattage, I would think. Am I missing something here?

 

<div class='quotetop'>QUOTE(jbarnhart @ Aug 28 2006, 10:32 AM) [snapback]310611[/snapback]</div>

It could absolutely be done. Is it worth $150 to have the dimming? No, they wouldn't cost anywhere near that much in mass production, but I'm guessing at a market of about 50 pieces - so all design and prototyping would have to be carried on very few units.

I know that some folks just love the dimming. I also know that they don't miss it when it is gone.

<div class='quotetop'>QUOTE(marjam @ Aug 28 2006, 12:48 PM) [snapback]310687[/snapback]</div>

Not sure what to explain, as I don't understand how different levels of LED lighting goes against what has been said. You can choose whatever brightness you want out of an LED. You can vary that brightness if you choose. You can do all that with current regulation. The "dimming" of interior lights is a different story, and specifically works with incandescents by design. Incandescents are basically voltage driven while LEDs are current driven.

I haven't recently read back through this thread... but you are correct that the Prius already has LED brake lights. All three areas. No different technology. Not sure what was said. If you can provide a quote, it would be easier to answer.


<div class='quotetop'>QUOTE(nerfer @ Aug 28 2006, 01:44 PM) [snapback]310726[/snapback]</div>

Nerfer -

LEDs are NOT more efficient at converting energy to photons yet. (we're getting there quickly though!)Though these things all vary, a good halogen is about equal or better in the energy-to-photon conversion process. The big difference is how that light is projected. A bulb just throws it everywhere, and you've got to collect it and send it where you want it. An LED has greater control over where the light is delivered even before the optics come into play. Because of the photon control, I can make an LED interior replacement lamp that is brighter than an incandescent (in the area where it is bing used) and uses less energy. The reason is because I'm using almost all the light, where the incandescent is throwing a huge percentage of the light away.

Heat is a very important element in all this, and there are big differences in the two technologies. An incandescent REQUIRES heat to work. You are seeing the result of a very hot wire throwing off photons. incandescent bulbs are very efficient little heaters. Only a fraction of the energy is released as light - but that's where it comes from - the heating of that wire. So again, an incan bulb will only work if it is hot. You don't want to keep it cool.

An LED, on the other hand sees heat as the enemy. Light is made in a totally different manner, and while the process happens, there is waste heat. The faster you can get rid of that heat, the more efficient that LED will be, and the longer it will last. High power LEDs give off lots of heat as waste, and you need some serious heat-sinking to make them work properly for a reasonable life span. (please note that the little 5mm and 3mm LEDs stay cool to the touch if driven at the proper current. They simply don't carry enough power to warm up. Increase the current - even a little bit - and you'll see those little buggers get hot to the touch in a hurry... and then poof, they're gone. They have no way of getting rid of the waste heat, so they are severely limited in the amount of current they can see.

Incan = heat good
LED = heat bad

But they both make plenty of heat.

Did I help or confuse?