LEDs: How bright is BRIGHT?

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RogerTango

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I am looking at this LED right now:
Luxeon III Emitter LED - Red-Orange Lambertian, 190 lm @ 1400mA [LXHL-PH09]

I am guessing its a 3w LED, which by the way... LED ratings and brightness details have all eluded me!

This one says its 190 lumens. Well, just how much light is that? What can it be "compared to" so I can figure out if it is bright enough?

The object is, I am building some road side warning lights. The red-orange color should be a good color. The pattern appears to be on target, I want it to be seen not just from the rear but from off-angles too. But I want it to be BRIGHT!

What LEDs are they using in emergency vehicle lightbars? They are amazing bright, Id only want about 4 LEDs on each side, in a 2X2 gang I would reckon would be good.

There are SO MANY resellers on the net of LEDs, and I have no clue how to determine which one(s) will suit my needs/wants.

Thanks-
Andrew
 
RogerTango said:
The object is, I am building some road side warning lights. The red-orange color should be a good color.
Click to expand...
There are international standards followed for the wave length(indicates color) for signaling lights. You can search for 'LEDs for road signaling'

The pattern appears to be on target, I want it to be seen not just from the rear but from off-angles too. But I want it to be BRIGHT!
Click to expand...

LEDs with high brightness and high viewing angle( to see from off-angle) are available

There are SO MANY resellers on the net of LEDs, and I have no clue how to determine which one(s) will suit my needs/wants.
Click to expand...
Decide based on reputation of the manufacturer (as an indication of quality), price and availability at your place.
 
You do NOT want that LED, you can not mount it. Hell, I have a production equipment at my beck and call and I can't mount it! You if you insist on a Luxeon III you want the star.

How are you going to use them? As flashers driven with 2A pulses you might get 230Lm out of them, but at steady on you can only get 40Lm due to the die temperature. (1A 120C die assuming out in the sun getting up to 65C)

At steady state you can get 50Lm at 700mA continuous from a Rebel.

A headlight is 1000Lm. A 40W 100V bulb spreads about 500Lm of white light all over. **broken link removed** covers this already. It is dedicated to LEDs.

Dan
 
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Thank you sirs for the help! I have some 10,000mcd LEDs that I applied 5v to and they are so bright, I think they will be well suited for my application!

Andrew
 
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Guessing that your 150k mcd LED have a 25 degree emitter angle, they are only 22 lumens. Not very bright.
 
mcd to lumen convertor:
**broken link removed**

so your 150kmcd 40 degree LEDS are 56.838 lumens bright
 
Source Material:InGaN !
Emitting Colour:10mm 40° 5-Chips WHITE LED
LENS Type:Water clear
Color Temperature: 7000K
Luminous Intensity-MCD: Min: 260,000mcd Max: 280,000 mcd
Reverse Voltage:5.0 V
DC Forward Voltage: Typical: 3.4 V Max: 3.8V
DC Forward Current:100mA
Viewing Angle: 40 degree
Lead Soldering Temp:260°C for 5 seconds
Intensely Bright

these are the white ones i got there even brighter
 
This is not a single LED. It is cluster of LEDs forming a small LED lamp. If your requirement is to make a street warning light, either you can select a standard lamp for that purpose (may not be white) OR make yourself with LEDs.
 
I ordered a 50pk of 160kmcd LEDs, and have sucessfully gotten a LM317 set to 3.5v to power the 60kmcd LEDs that I now have, so I think I can get this project to work like I want.

Cheers,
Andrew
 
Hi,


I've used quite a few of the white LEDs in the past and present.
The Luxeon 1 watt white LEDs are pretty decent i guess. The
star is easiest to use but you should still use a heat sink for
best results.
The Luxeon 1 watt emitter can be mounted, but to do so you need
some thermal epoxy. The idea is to mount it to a heat sink like
aluminum or copper with the thermal epoxy, using a very thin layer.

I also used the 1 watt emitter in a super small flashlight but under driven
to only 100ma instead of 350ma as it's rated for. I didnt need a
heatsink for that current level and get an acceptable level of light
out of it using a small li-ion cell. The whole light came out only
3 inches long and 5/8 inch diameter approximately.

I use these LEDs every day, and one star i keep on 24 hours a day
7 days a week and it works pretty well (with heat sink of course).

Some people run their stars without an additional heat sink but
i really dont recommend that because they get too hot.

Also, lumen depreciation is highest at full rated current and much
much lower for an under driven LED.
 
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I have a clock radio that is about 25 years old. Its red LED display got dimmer over time and now that it has lighted for about 219,000 hours I can hardly see it in the daylight.
 
RogerTango said:
I ordered a 50pk of 160kmcd LEDs, and have sucessfully gotten a LM317 set to 3.5v to power the 60kmcd LEDs that I now have, so I think I can get this project to work like I want.

Cheers,
Andrew
Click to expand...

Are you not using a series resistor with each LED? What value you are using?
 
It really gets tiresome being endlessly polite on this topic. Rebels put out as much light as the brightest generic Luxeons for half the power and does not require thermal epoxy to do it.
 
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Ubergeek63 said:
It really gets tiresome being endlessly polite on this topic. Rebels put out as much light as the brightest generic Luxeons for half the power and does not require thermal epoxy to do it.
Click to expand...

"It really gets tiresome being endlessly polite on this topic."

I would never accuse you of being endlessly polite
 
I think Luxeon LEDs should have a "best before" date. Or a warning that better ones are available. Then the old ones can be used as replacements in old circuits and the new ones can be used in new circuits.
 
premkumar9 said:
Are you not using a series resistor with each LED? What value you are using?
Click to expand...

The LEDs I just bought from China (the 160k mcd) are supposed to include a resistor for each so it can be driven off 12v. I do not know what the value is supposed to be, when they come in Ill report back with the resistor that is included. Id like to try it both ways, with the included resistor and an LM718 set to 3.5v.

Andrew
 
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