Luxeon III False Claim?

So I purchased one of thess automotive 7440 Red "Luxeon III" bulbs from this autolumination site (first product on page):

http://autolumination.com/7443_7440.htm

Once I got it, it wasn't nearly as bright as I expected it to be, so I finally took a reading on the current it was pulling and that = 150mA(!)

Correct me if i'm wrong, but shouldn't a Luxeon III emitter, correctly driven, pull around 700mA and be able to handle up to around 1400mA?? Is there any other way to verify this is *not* a Luxeon III? I am disappointed at their false claims

How are you driving it


NM, just looked at the product page.

$20 bucks sounds a bit on the cheap side, does it look like theres any kind of regulation circuitry in there?

I ordered one of these and it is pretty bright, just about right for a 1 watt, something must be wrong with that one. Maybe return it and try the 3watt version from superbrightleds.com

kakster said:

How are you driving it

$20 bucks sounds a bit on the cheap side, does it look like theres any kind of regulation circuitry in there?

Click to expand...

Hard to see through the red plastic, but looks like a resistor, surface mount IC, and some other rectangular object...maybe a diode or rectifier.

Justintoxicated said:

I ordered one of these and it is pretty bright, just about right for a 1 watt, something must be wrong with that one. Maybe return it and try the 3watt version from superbrightleds.com

Click to expand...

The site claims it is a 3-watt LED


.

150mA at 12/14.4V? Remember, the lux runs at 3V-4V range. So at 150mA at 14.4V (avg voltage that auto power systems run) its about 2.16 watts of juice being used -


also, just because its a 3Watt LED doesnt mean theyre putting 3watts through it

True, I guess I forgot the fact that I am measuring the current based on a higher voltage.

Suppliers are getting into the bad habit of stating the emitter's rated wattage instead of what they are driving it with.

For instance, the TerraLUX MaxStar5 is called a 5W drop-in for your mag, but it actually consumes about 1.9-3.6 watts from the batteries (depending on 3, 4, 5, or 6 cells used). (Confirmed among a couple users)

There is even less wattage at the emitter, due to driver efficiency loss.

Is it a 5W drop-in? You be the judge.

In my opinion, what good is 100 Watt [capable] light bulb if it only produces 50 Watts at any given time during it's lifetime? Would you feel it's acceptable for it to be sold to you as 100 Watts?

EngrPaul said:

In my opinion, what good is 100 Watt [capable] light bulb if it only produces 50 Watts at any given time during it's lifetime? Would you feel it's acceptable for it to be sold to you as 100 Watts?

Click to expand...

Like the 13W flourescent 60W bulbs? :touche:

myk said:

Like the 13W flourescent 60W bulbs? :touche:

Click to expand...

These lights say right on the package 13W = 60W in big letters to give consumers their reference to what they already know.

My point is equivalent to someone selling a 13W fluorescent and having it driven to 7W.

My point is equivalent to someone selling a 13W fluorescent and having it driven to 7W.

Click to expand...

Like in fluorescent camping lanterns...

myk said:

also, just because its a 3Watt LED doesnt mean theyre putting 3watts through it

Click to expand...

That's the thing, it isnt a 3 watt LED, it's a Luxeon III.

Unfortunately it's become common to call the Luxeon I a 1 watt, Luxeon III a 3 watt and a luxeon V a 5 watt.

We've become too used to the wattage claims of 120 and 12v bulbs, where the voltage is always the same. LED's are varying voltages, so the wattage claim wont be true unless it is driven at that specific wattage. Luxeon III's can be driven anywhere from 0 watts to 4.5 watts, if they are cooled well enough. If driven at their binned level of 700mA then the Luxeon III is more like 2-2.5 watts typical.

With poor heatsinking, such as these replacement lamps use, they have to be driven at lower current levels to prevent them from overheating.

I ordered one of these (white color) a while ago for the curiosity factor. The LED itself is clearly a LuxIII. The base is opaque so I can't see what's inside, but connecting it to a regulated power supply I measured 110mA at 14v and it maintains constant brightness down to 4v (290mA) and up to 18v (90mA), so from this fehavior I guess it's fair to assume that it has an LM317-type voltage regulator driving the LED. From these numbers it looks like it consumes 1.54W @ 14v, which means the LED gets .375 W ( (3.4 / 14.0) * 1.54W ) and the rest gets turned into heat in the regulator. The heatsink is a farily good design, but it looks like it's made of polished Nickel or a similar alloy which would make it neither a good heat conductor nor a good heat emitter and IMO it is far too inadequate to dissipate 3W if you were to drive the Lux at that level. The brightness level is about the same as a single Nichia CS, so I think it's pretty much a waste of $ and technology when you could replace the whole thing with one 5mm Nichia and a series resistor.

so from this fehavior I guess it's fair to assume that it has an LM317-type voltage regulator driving the LED.

Click to expand...

Nope, not at all. If an LM317 were used as the current regulator, then current draw would be constant across all input voltages. The LM317 is a linear regulator, meaning that the regulator drops voltage to maintain regulation. The current into the device is the same as the current to the load.

The behavior you're describing is typical of a switching DC-DC converter. These will deliver more current to a device than they draw from the supply when the input voltage is higher than the output voltage.

evan9162 said:

Nope, not at all. If an LM317 were used as the current regulator, then current draw would be constant across all input voltages.

Click to expand...

May well be. But what if the LM317 was configured as a voltage regulator, not a current regulator?

BTW, I just double checked my figures and it looks like Lux III's Vf is around 2.1v at 110 mA not 3.4v as I had assumed.

frenzee said:

The brightness level is about the same as a single Nichia CS, so I think it's pretty much a waste of $ and technology when you could replace the whole thing with one 5mm Nichia and a series resistor.

Click to expand...

I typically hook 4 LED's in series rather than waste the power through heat in a resistor. Four 5mm LED's can be packed quite tightly together and they run very cool while putting out a lot of light due to their increased efficiency at lower current.

frenzee said:

May well be. But what if the LM317 was configured as a voltage regulator, not a current regulator?

BTW, I just double checked my figures and it looks like Lux III's Vf is around 2.1v at 110 mA not 3.4v as I had assumed.

Click to expand...

Doesn't matter - it works the same regardless of how it's configured.

(post erased)

You seem to be rather confused.
An LED is a (more or less) constant voltage device.
Feed it 1mA, and it (luxeon) LED will drop around 3.1V.
Feed it 700mA, and it'll be closer to 4V.

You simply cannot feed it 100mA, and expect it to know you want it to run at 10V, it doesn't work like that. It's sort of like connecting a shaft running at 6000RPM directly to the wheels of a car, it doesn't automatically slow it down, and provide the same power output.
Either the car wheel will explode (the LED blows) or the motor stalls (the power supply shorts out)

You need something to regulate the voltage down - this can be a linear regulator or resistor, (like a clutch) for very inefficient results, or something like a gearbox - a switched mode power supply.
google luxeon driver 1w and ensure that it will cope with the input voltage you are using.

No I understand all of that speedevil - I was just thinking on other terms, confusing myself - hah ...nevermind ... post edited out