Is mc-e more efficient?

[kicken_bright]

When I heard about the mc-e and similar P7, I thought this was the new generation of efficiency lighting! However, I have read some more, and have found this may not be the case. Since many of the new mc-e or P7 lights are aimed for flood, wouldn't it actually be more efficient to run a multi led light? maybe something with 4 R2s? I'm just not seeing the big deal about these multi-emmiter single led's. I think the R2 has it beat in the throw category, and also in the efficiency department. What do yall think? :thinking:

 

[monkeyboy]

The quad die will have more throw relative to the lens diameter than the 4 individual reflectors. In theory at least.

Consider a single die LED in a reflector.

Scale the whole thing x 2 (area x 4). Simple geometry; the beam divergence stays the same while the power output increases by 4. This is the equivalent of a quad emitter with 2 x diameter reflector (reflector height x 2 also)

To produce the same effect, we need 4 individual reflectors and LEDs. arranging 4 together requires an encompassing circle that is a factor of [1+sqrt(2)] larger ~2.4 x.

In practice, there is a gap between the dice of the quad emitter which affects things.

 

[EngrPaul]

Go to the review section and compare the two versions of the Lumapower MVP. This will give you a good idea.

The efficiency of a LED is inversely proportional to the temperature of the die. Multi-emitter lights can dissipate heat more effectively than a single-emitter light, all things equal.

Now the ability to get the light out the front end and shaped the way you want the beam to be is another story.

 

[1996alnl]

If your only used to Q5's ,R2's etc...
You'll be blown away with an MC-E, a MC-E driven at 350mA per die or 1400mA total will produce i'm guessing 400+ lumens.

So in theory i don't think it's more efficient just alot more powerful.

 

[lights]

It's just the same as the Lux I and Lux III vs the Lux V of yesteryear, right?

 

[Saint_Dogbert]

I believe a Cree MC-E is just 4 XR-E LEDs on one die. So there is not really any technology that is new per se that is going into an MC-E. However, a LED driven at a lower current of say 350ma will have higher efficiency (more lumens per watt) than a LED driven at a higher current like 1000ma. The LED driven at a higher current will produce more lumens overall, but at a lower efficiency. Therefore, an MC-E will probably be more efficient producing 350 lumens than an XR-E producing 200 lumens, since the latter must be driven harder to reach that output. But if you are going for absolute output in the 700+ lumen range, I don't know that the MC-E will have an efficiency advantage. It would make for a smaller simpler light, though.

Multi-die emitters produce more flood by nature because they have a large emitting surface, so it is harder to get a tight beam. But you'd have the same problem with a multi-emitter light, as it would be pretty hard to collimate all the beams together.

 

[kicken_bright]

alright, I kinda get it... correct me if I am wrong:
R2's are best at throw.
4 R2's driven at 350mA would be a better flood light than an mc-e driven at 1400mA.
But the mc-e is an in between. It can produce a lot of light from a single emitter. That way you can still fit an mc-e into most reflectors and give it some throw!

does this sound right?
but for those who want only flood, wouldn't it be more efficient to use 4 R2's? Is it possible for example to fit 4 R2's in a p60 and drive them at 350 mA each?

 

[AaronM]

For a given reflector size and single emitter package, an XR-E will out throw an MC-E.

Again, assuming just one emitter VS another, the MC-E will be brighter given the same power (wattage = volts X amps).

Of course it's possible to get floody light from an MC-E, too easy: Just use a smallish reflector. My MC-E modded L4 is an awsome pocket flood light.

Hope this helps.

 

[EngrPaul]

4-die run at a given power is more efficient than a 1-die run at the same power, due to the fact that LED's are more efficient at low power. Only problem is, this larger surface area of the die is harder to focus with the same size reflector.

4-die run at a given power is less efficient than four 1-die single emitters, each running at 1/4 power, due to heat. Only problem is, this is not as efficient to build cost-wise.

I think the latter is what the OP was asking.

 

[kicken_bright]

Alrighty! I understand now! Thank you everyone! I believe the ability to ask a question and receive an answer is what this forum is all about!!!!!!lovecpf