MC-E or P7 behind a small reflector?

[Gryloc]

I was thinking about waiting for my MC-E to arrive before judging whether to place either it or a D-binned SSC P7 emitter into my new Jetbeam III flashlight. The Jet-III Pro sports a relatively deep and slightly textured reflector with a 24.5mm diameter.

Sabrewolf has placed a P7 into some Jet-III Pro flashlights, and the beam is a bit larger than with the stock Cree XR-E. Would I be happier with the MC-E behind the reflector? I understand that the MC-E produces a noticably larger beam due to its larger apparent die size, but how would it compare next to a P7 in a small reflector? Thanks all for your assistance. :wave:

-Tony

 

[degarb]

So apart from fixed lighting and short burst lights I would never use, what is their advantage of the P7 and MC-E for personal flashlights? Reading here, it dawned on me that at least a R2 based MC-E ran at 50 milliamps per die in parallel, would offer a whopping efficiency of 140 lumens per watt, with option for go 12 watt for burst. Not bad for a flashlight, as long as the optic kept pace to gather and take advantage of the inverse square law that applies to columnation, as well as distance. Now for the P7, I am guessing you would need some inefficient boost controller that would obliterate lumen per watt number for a p7 to run from a practical batter pack. (I don't get lumen per watt numbers for 2 AA boost controllers with something like an XR-E, that cut lumen per watt drastically.)

I have, here to fore, only been casually reading on mc-e and p7. Not fully interested, since I figured too high voltage/wattage for a practical headlamp with batteries that could last a full 8 to 10 hours. But I am reconsidering, and eager to be convinced that my light requirements can be met with advantage with these two super powered emitters.

 

[phantom23]

Would I be happier with the MC-E behind the reflector? I understand that the MC-E produces a noticably larger beam due to its larger apparent die size, but how would it compare next to a P7 in a small reflector? Thanks all for your assistance. :wave:

Larger beam, hotspot and more artifacts.

 

[Gryloc]

Thanks for the reply. From what I have been reading lately, it confirms what you say, phantom23. I guess that there would be less of a corona around the beam with the MC-E compared to the P7 because P7 uses that glob of phosphor on its dies, while the MC-E has a clean and defined conformal layer on its dies. I guess, like the SSC P4, that "gooped on" phosphor helps smooth out the beam a bit. So, a LOP reflector will help clean the artifacts up a bit with the MC-E, and the use of a bigger reflector will tighten up the beam.

I guess I will have to wait until I get both emitters to see which looks nicer. I wanted some good punch (throw) out of my Jet-III Pro, but I understand that with either emitter, there will be less of it. It is down to which will produce the least floody beam. ...Well, I suppose I will wander off topic a bit (its my thread ):

degarb,

I am not fully sure that was an answer to my question, but I understand where you are coming from somewhat. Any LED driver circuit will have losses. The best bet to take advantage of the LED technology, given you have a really low capacity battery or where efficiency matters, is to direct drive the emitter (or use a PWM driver which really takes advantage of LED efficiency when set at a low duty). Fortunately, the Jet-III Pro uses a li-ion cell, so there is less loss from the buck circuit than what you would see from any boost (plus I want too keep the driver for nice, programmable modes). The P7 has a fixed Vf that is in the range of 3 NiMH cells or one li-ion. Just design the light around the requirements. The MC-E can be wired in different configurations to meet your battery needs. You may need a boost driver if you want to power the MC-E when wired in series, but the design is up to the modder.

I do not see why you are uninterested in an MC-E or P7 in a flashlight. The main reason I want to trade out my Q5 XR-E out of my Jet-III for a P7 or MC-E is because of the added efficiency that they offer. This has me interested for two reasons:

First is the WOW factor. I can crank this light up to max (1.3A to the emitter), and see up to 400 or more emitter lumens from the quad-die LED emitter. That beats the pants off of the rated 275lm at the emitter from a Q5 XR-E (Jetbeam quotes 225lm, so that must be out the front).

Second is the ahh factor. Where I can get more light in the lower modes than with the stock Q5. That means for the same brightness of one mode with the Q5, I can operate at an even lower mode with the MC-E and extend my run time. Just remember that you do not have to treat these 10W power monsters as power monsters. You can seriously underdrive them for the added efficiency that they offer. Not everyone can cram four separate LED emitters into a small flashlight, so these quad-die emitters are wonderful! :candle:

-Tony