Brightest most effecient red LED to date right now?

[Zero_Enigma]

Just wondering what the brightest red LED is right now is out there. Looking to build a serious 2x red LED tail light. Was also wondering if there is a cheap driver that does high/low/flash all in one other then the B/N Flex?

I prefer to have the B/N Flex up front (as I can see the modes being used with all the modes that driver has) and as simple a light control in the rear of the bike (thus 3 mode and non of this 10 mode stuff and SOS blah....:scowl

I'm also in the works of making a rack mounted tail light which I plan on putting a momentary switch to the red LED's so I can show that I'm slowing down as I press the switch. I've found so many drivers can't tell when you're slowing down and 95% of them don't understand (dispite it beingin the drivers handbook and part of the flipping exam) the hand signals to slow down.


Zero_Enigma

 

[alexlockhart]

I can't give you recommendations for brightest or best red LED, but I'm building a taillight with a red-orange Cree from Cutter. It's spec'd for 86lm at 700mA, which in my playing with it on the bench, is more than bright enough. I'm using a Carclo 14x37 elliptical optic with it, to put light exactly where cars are (and not up in the sky or down at the ground) and when driven at 500mA, I estimate that any spot in that very wide beam is twice the lux of the much smaller bright spot from my PB Superflash, which is far and away the brightest batteries-included commercial taillight.

I chose the red-orange one because it had almost twice the lumens of the red one at the same drive current - not sure why it's so much brighter/more efficient. The color looks like a normal red taillight color; it's practically identical to the color of my Superflash and my 2 Cateyes that have 5mm red LEDs.

For driver boards, it sounds like you might be well-served by one of the cheap DX drivers. Some of them have 5 modes: 3 brightness levels, strobe, and SOS, which might work well for a taillight. I think they're only designed to drive a single LED, not 2 or 3 in series, but they're cheap enough to get 2 or 3 and have them each control its own LED if you want. Be aware of their input voltage ranges, though; some of them are boost (for single Nimh/alkaline cells, 1.5V) and some are buck, with ranges up to 4.2V or 9V or something.

I'll be driving my rear light in an unconventional manner: with a voltage regulator and some switchable series resistors to give me high/low levels. Since it'll be powered by my main 12V battery pack, none of the cheap DX drivers would work, and those that can handle the input voltage cost $15 or more. I'll regulate the voltage to about 2.6V and use resistors to drive the LED properly, using jtice's excellent LED_pro program to calculate resistor values and drive levels. No flashing mode, but I think my taillight will be bright enough as is, and I don't think blinking rear lights are such a good idea anyway.

Hope this helps!

Alex

 

[Zero_Enigma]

I was thinking of using a Ledil Flare myself for coverage. I was thinking of using 2x Flares then two large lenses with yellow LED's hooked up to a momentary switch running off say 4xAA on a boost regulator for when I'm making a turn. I will still be using the arm signals but then people will equate the turn signal to the arm signal then can finally and hopefully have the damn cagers learn the arm signals. When I signal now seriously people wave back or don't know WTF your arm is going. FUnny because when you get your drivers licence your handbook also shows the arm positions as well and it's ALSO ON THE EXAM as well. At least I had it pop up on the computer exam when I got my drivers lic. yet these danm drivers still don't know hand signals. I'm not going to risk anymore to find out who knows and who does not. I fI use a turnsignal then use my arm and something they understand then so be it. At least it's understood I'm turning left.

In the front of the bike I already use two blinkies on the top as 'cats eyes' and also improvied turn signals if I'm at the left turn or right turn lane. I have three lightsup front on the bike. The middle one is static and the left/right is the one that blinks while the other is solid so when someone looks at it they see one side blinking as a triple set of lights wide and it registers as a turn signal. Tho still at a left turn lane you still get people stopped wondering to let you go or not andI stil have to wave them forward to go. If I was a car would you still stop for me to turn left unless I had a dedicated left turn lane? No, because the left turn lane must yield tot he oncoming traffic till the lanes are safe and clear to make a turn just like a car yet sometimes you get people that just freeze up.

Anyways /rant. Back tot he lighting. I want the brightest red LED or semi red LED to date for the project.


Zero_Enigma

 

[Zero_Enigma]

I take it this is the brighted red LED on the market today? Given I think I read somewhere that Dinotte uses them and drives thier LED at 1.5A to get 140lm.

3.4v vf which I'm assuming is ~500mA given that SSC P4 @ 3.7v is (if my memory is correct) 1A

 

[sbothwell]

Dinotte are almost certainly using red-orange Lux III's running at 1.4A to get their 140 lumens output, since that is the rated value of a red-orange Lux III. You can also get a red Seoul P4 which should do about 50 lumens at 350mA and 100 lumens at 800mA, with possibly a lower Vf than the Lux III.

It looks like you might have a trade off - more lumens at the top end from the Lux III or more efficiency from the Seoul (I havent found specs for Cree red power LED's although I notice Kai is supposedly selling XR-E reds). Both the Seoul and the Lux III are available from http://www.dotlight.de

 

[Zero_Enigma]

I'm using a DealExtreme 3.6-9v @ 800mA regulator which can take up to 2xLED's. Tho I would like to get the most lumens I can at 800mA and use say 9v of power to drive one unit for a long time.

 

[alexlockhart]

If the LuxIII can produce 140 lumens, I'm pretty sure it's the brightest red LED on the market. However, I think that there are regulations (in Canada also) regarding the brightness of rear lights on vehicles, and that may be too much. Of course that doesn't stop DiNotte, and many DIY'ers, from making lights that bright, even though most of them probably throw away a lot of the light by pointing it up in the sky and down at the ground - using wide-angle round optics. Brighter is better, but I think there is a limit to that.

My red-orange Cree, at 86 lumens at 700mA, won't win any brightness contests against the others mentioned, but with its low Vf (compared to the LuxIIIs at least) it very well may be more efficient. Here's the datasheet.

I didn't know any of the cheap DX driver boards can drive 2 LEDs in series. Is that mentioned on any of their product pages? They all look like they're designed for one. Which one are you using?

Alex

 

[Darell]

Good discussion on the reds. I've had the same questions. I do agree about the orange/red - forever they've had more output than the "red."

As for driver, I can't see a benefit of using anything else but the nFlex or bFlex for this. You'll be able to control the brightness for a variety of situations to save battery or to be EXTRA bright, you can set how you want "power on" to work, etc.

 

[Zero_Enigma]

I'm using a DealExtreme 3.6-9v @ 800mA regulator which can take up to 2xLED's. Tho I would like to get the most lumens I can at 800mA and use say 9v of power to drive one unit for a long time.

Link to regulators here

Those are what I'm using to run my dual (skeleton wire el ghetto :sick2::mecry SSC's with right now. Works well but need a better heatsink then mounting two on a 486 heatsink. >_<;;


Darrell:
BTW have you and George considered to make a uber simple regulator board for taillight DIY'ers? I see a market here. Say 3-4 modes 250mA/low, 500mA/high, low strobe, high strobe.

Without all the modes and such of the n/b Flex which while nice I kind of prefer that up front for main lighting.

 

[alexlockhart]

As for driver, I can't see a benefit of using anything else but the nFlex or bFlex for this. You'll be able to control the brightness for a variety of situations to save battery or to be EXTRA bright, you can set how you want "power on" to work, etc.

. . .

Darrell:
BTW have you and George considered to make a uber simple regulator board for taillight DIY'ers? I see a market here. Say 3-4 modes 250mA/low, 500mA/high, low strobe, high strobe.

Without all the modes and such of the n/b Flex which while nice I kind of prefer that up front for main lighting.

I agree with Darrell, that I can't see any benefit of using any other driver but the xFlex for almost any LED-driving purpose. If you want simple taillight operation, run the UIB2 in duo-mode.

The reason I'm doing something different for my taillight is cost - I don't want to spend $30 on a taillight driver when the simple operation I want can be had from $5 DX drivers or, in my case, a $5 adjustable switching buck regulator and 2 switched resistors for high and low mode. Correct me if I'm wrong, but Darrell and George can't compete with cheap Chinese mass-produced boards for $5 - they can build something far better, and charge more, and corner a different part of the market.

Nice to know that those cheap regulators can drive 2 LEDs in series. Just yesterday it was pointed out to me in another thread that these drivers should be able to output up to whatever their input voltage is minus the 1-2V for the driver, so if it can take 9V in, it should easily drive 2 LEDs in series. I feel silly for not thinking about it in those terms, I just read what was on the product page and assumed it meant only 1 LED.

Alex

 

[BentHeadTX]

Just found this thread and thanks for starting it.

Presently, I use a PB SuperFlash running in constant on mode and want to use a better tail light. Those Cree orange-red LEDs look to be the way although I am not sure how well a simple LED swap would work. Maybe put some more copper inside to take the heat?

The ultimate would involve three Crees, special optics and a xFlex with UIB programming.

If you want the light just to stay on and generate light, there might be a very easy solution. Maybe a cheap 2AA LED light that sinks heat well? Swap the stock LED and rip out the boost curcuit. Use two Eneloop AA NiMH cells and turn it on. The initial spike of voltage might hit the LED at 1,000mA but it should drop within seconds to 600 to 700mA. I would put a very low ohm resistor (1/10 ohm) inline to prevent the fresh battery spike. The Crees would be pulling about 80mA at 2 volts while generating over 10 lumens. When your light is not very blinding anymore, recharge the Eneloops.

The problem with direct drive is the runtime (crap) Time for a stout high-wattage variable resistor. It would be much easier if Sanyo made their LSD Eneloops in a D size but... a 2D Mag tail light might be a little over the top.

 

[IsaacHayes]

The red-orange color is the way to go, it's the same color as incandescent red filtered tail lights. Cherry red LEDs appear less bright to the eyes anyways, and even red Luxeons don't seem that cherry red to me anyways. So red-orange is the best bet for lm/watt and brightness.

The luxeons have very good lm/W. The luxeon 1 is normally a S or T bin, ~60lumens at 350ma (1W). The luxeon3 r/o is like 4 luxeon1's in parallel in the same package. The die is 4x as big, and takes 4x the current (1.4amps), and puts out roughly 4x the light, (a little less lm/w due to so much wattage in one package).

So a lux1 at spec or lux3 r/o somewhere under 1.4amps should have very good lm/w.

No idea about the cree leds, or others. But cree does not make their own Red dies. and there is no color XR-E other than blue and royal blue at this time.

 

[Darell]

Darrell:
BTW have you and George considered to make a uber simple regulator board for taillight DIY'ers? I see a market here. Say 3-4 modes 250mA/low, 500mA/high, low strobe, high strobe.

Without all the modes and such of the n/b Flex which while nice I kind of prefer that up front for main lighting.

Not sure I really understand. There's no multi-level driver more simple than setting a bFlex to duomode, and 500mA max. You can then set the low to whatever you want, and presto - uber simple. You have two levels of constant and two levels of blink - without one getting in the way of the other. And then when you realize the error of your ways, and want all the levels available - they can be turned back on in a moment without having to swap out the driver or change sense resistors.

We don't just toss out UIs by accident! We actually think about them!