Seoul P7: Cool LED but what am I missing?

[McGizmo]

Hi guys,

I am late getting on board with the Seoul P7 but I have now played with one a bit; perhaps not enough though.

For starters, I think it is a really cool package and certainly energy and photon dense! I have an idea for a MCPCB that would serve as both host for the P7 as well as the Seoul AC LED and it would be fun to have such a board. However what would be the application?

Well one obvious application is a flood light because you have a lot of photons coming from essentially the same location. If you need a high flux flood source in a small footprint, I think the only other LED that could give the P7 a run for its money would be a cluster of 4 Rebels but are viable Rebels available at present? :thinking: :shrug:

Now with the flashlights, the typical requirement is one of some collimation of the light. Although the P7 package is small considering the 4 dice it holds and certainly one boasting good efficacy, the "image" these 4 dice make is not small. We are back to the scale of the Luxeon 5W here in terms of photon management and considerations.

Although the P7 itself is relatively small, in order to manage its photons and thermal output, you likely need to consider a sizeable host. Once you scale up for this host, it seems to me that you can now consider the alternative of clustering smaller high power, single die LED's with their own optics which can accomplish the same distribution of light and possibly with a smaller piece of real estate.

I think it all boils down to just what you want from a light and what are your various means of reaching your goals.

In terms of single LED and single optic with maximum flux, the Seoul P7 is an obvious contender if not winner. It would depend on the criteria of the contest to see if the Osram Ostar might prevail here.

I have had a few people contact me regarding a reflector for the P7 and as a number of you have already determined, some of the McR reflectors seem to do fine with the P7. I am sure some tweaking of their design would better optimize a match but I personally don't find myself getting all pumped up about this LED.

I suspect part of my "problem" is that I have come to really like the beam distribution of the Cree XR-E in the deep and short focal length reflectors with the McR-17XR probably being what I consider to be optimal. It seems to me that I can cluster 4 of these and in a smaller diameter accomplish what I would want with a high output "throw" type light compared to what I could get from a P7 and single optic. Input and output powers in watts would be comparable. For that matter, with a viable Rebel, I can even get some cool beams from smaller packages in cluster.

There seems to be a parity in terms of lumens/watt/dollar comparing these various LED's with the dollar representing cost of LED. Clustering optics is more expensive than the single optic but in the big picture, I am not sure how much of a burden this represents.

I posted this thread here in the McGizmo forum because I didn't want to stir up any trouble in the general LED forum especially since my focus here is on my activities and my need to grasp the nature of the Seoul P7.

I suppose I should add that there is also the issue of driver for this LED. At this point I have issues for drivers of any sort so that in itself is probably not significant but none the less..

What am I missing here guys? :thinking: :shrug:

 

[Kiessling]

Since I have no clue about anything I probably should just shut up, but I can't


One difference would be Vin. Roughly 3V vs. 12V of a string of 4 Crees in series. I have no clue how this affects drivers, but we sure know that a string of LEDs driven at high currents aren't an easy thing to do for our current drivers. If the P7 is better ... :shrug:

Then ... there's the coolness factor. It is BIG. It has POWER. HAW HAW HAW.

The light with the P7 might be less complex than the light with 4 Cree and thus less prone to failure.

But in the end ... there is wisdom that the Cree beam with the McR-xxXRs is just about perfect.

bk

 

[vinsanity286]

One thing that I do not quite get about the P7 is the apparent amount of heat they generate, though I have not received mine yet so I do not know first hand.

Does the P7 create more heat than 4 crees driven at the same current? Is it simply because of the more concentrated source of heat as opposed to 4 separate emitters?

Perhaps the biggest advantage of the P7 will be under driving it in a smaller host such as a 6p or other 2 cell lights, and still getting a large jump in brightness over a cree.:thinking:Just some thoughts....

 

[vinsanity286]

oops..How do I delete double posts?

 

[vinsanity286]

sorry tripple post stupid computer:sick2:

 

[acourvil]

I think I've heard that before . . . .

I don't think that they generate more heat than 4 individual Crees, but because it is concentrated in a smaller area, I think the heat transfer solution is more difficult and there is a greater potential for a problem.

 

[Thujone]

I think an 18650 Mule would be awesome with the P7 in it...

 

[McGizmo]

The low Vf is enticing and you can underdrive the P7 effectively and then the thermal considerations are not so paramount. However, you still face the need of a large optic if you seek collimation or in the case of a flood, how many lumens do you require? If you say drive the P7 at 500 mA you might get 10-20% more flux than you would from driving a single P4 or XR-E at similar power but this is at the expense differential of the P7 over a single P4 or XR-E.

I think Bernie hit on the coolness factor of a big and hefty output but I am interested in identifying any applications where this actually gives you something you need or want and can't get by other means.

Although it is probably a poor analogy, let me equate the current high power, single chip LED's to a state of the art 4 cylinder engine. Now we have the P7 which is a 16 cylinder engine. What are the legitimate applications where you need a 16 cylinder engine?

To be more specific, lets look at the 500 and greater lumens the P7 can deliver. When you need this much flux, what is the distribution pattern of the beam and what is the likely size of the light? What are the applications for this light?

I believe we can thank PK and SureFire for the existence of the P7 and I haven't had a chance to see any of the proto's the LED will be used in but I believe they will be bright, single optic lights. I also expect these lights to find their own markets. BUT, for whatever reason, SF has not gone down the path of clustered high power LED's like many others have. I don't know the reason behind this and I trust there may be a good one that has eluded me so far. :shrug:

With the fact that the P7 is a SMD device and it has a non neutral slug, I believe a MCPCB is the best choice for its mount. To get significant thermal spread in the MCPCB I suspect you are now at a size where you could also consider mounting multiple LED's in a similar footprint and this is really no extra expense or difficulty. Once you go multiple LED's you can also play with different bins in regards to tint, color temp or CRI if you wish and possibly get a more balanced or wholesome integration of light.

I think the P7 is cool too but the first light that it entices me to make, personally, is a mule on steroids and I am not sure that beyond the novelty, I would find much need in such a light. My problem is I don't need that many lumens typically and only consider the need when I want to reach out some distance with a light. I am very impressed with cluster packages in this application and to get comparable distribution in beam with the Seoul P7 I suspect I would need to go to a 3" diameter reflector.

I definitely need to put some more time in with the P7 but I was hoping some of you who have already messed with the P7 could point me in a direction I haven't figured out on my own.

If it makes sense to come up with a "McR" for the P7 even if I have no plans or use for it myself, then it is something I should consider. On the other hand, I have plenty of stuff to deal with that is much more important and even critical for me. Before I blow off the P7 as "not interested", I want to get a better idea of what it is about.

 

[addictedmatt]

I think the price has a lot to do with it. For $60 - $70 (mag host, led, heatsink ect.) I can have 700+ led lumens.

 

[Kiessling]

Well, SF managed to put the P7 in the invictus which does not look big enough to support 4 x Cree.
And ... the LuxV was really able to shine in a smallish 27mm reflector.

So... maybe there actually is a way to use this LED in smaller lights with a reasonable beam.



But after all ... who needs a justification for buying a muscle car anyway? :nana:

 

[:)>]

Don,

2 Words for you...

3-Level HD45 w/a P7:thumbsup:

Goatee out.

 

[mbely2]

I was hoping that P7, when become available, might replace LuxV in my U2, making U2 a Ferrari of flashlights
I thought that this mod will be relatively easy.
Is this expectation reasonable?

Mark

 

[vinsanity286]

I think the biggest potential of the P7 is in a light such as the Super Flashlight V, a light that is designed around the P7 to be as small as possible while maximizing its potential.

 

[acourvil]

Well, it does give you the ability to have a single emitter light that can go from just usable to really blinding.

And it's always fun to try something new . . . like an Aleph 3-P7:

A3 with a DB917:

A3 with a P7:

With a 60 ohm McE2S, this light has a very comfortable low level "walking around" mode, but can go to "wow, that's bright" mode, too.

 

[toby_pra]

I think a regulated P7 Mod would be a great Idea...t should also fit
smaller bodies, than 4*cree, or? for that would be most impotant
as EDC

 

[270winchester]

like the Lux V, the thought of the McR45 with the P7 makes me drool...

 

[iconoclast]

...
I think Bernie hit on the coolness factor of a big and hefty output but I am interested in identifying any applications where this actually gives you something you need or want and can't get by other means.
...
To be more specific, lets look at the 500 and greater lumens the P7 can deliver. When you need this much flux, what is the distribution pattern of the beam and what is the likely size of the light? What are the applications for this light?

I believe we can thank PK and SureFire for the existence of the P7 and I haven't had a chance to see any of the proto's the LED will be used in but I believe they will be bright, single optic lights. I also expect these lights to find their own markets. BUT, for whatever reason, SF has not gone down the path of clustered high power LED's like many others have. I don't know the reason behind this and I trust there may be a good one that has eluded me so far. :shrug:
...
To get significant thermal spread in the MCPCB I suspect you are now at a size where you could also consider mounting multiple LED's in a similar footprint and this is really no extra expense or difficulty.
...

If I may endulge in some speculation for a moment...
I suspect that as engineers we tend to dismiss the "cool" factor in favor of measurable pros and cons. It does however play a role in actual light sales though. Fortunately, corporations tend to have entire departments of non-engineers to handle that sort of thing.
Now stepping outside the cpf world for a moment, multi-led lights can be picked up for very cheap. In most cases, these have multiple cheap 5mm leds to produce the light that could've come from one high power led, but the manufacturer presumably can get multiple standard 5mm leds for cheaper than one high power emitter (and doesn't care about the beam profile). The more expensive led lights (again by non-cpf standards) tend to have a single emmitter with a single reflector, etc. While all of us here know better, it's possible that the average non-cpf flashlight buyer has some preconcieved notions about the quality/price/etc. of multi-emitter lights.
Now what does a corporation do when they want to put out a multi-led light but the marketing department worries about the situation described above? Easy. Put those multiple leds under the same dome. Or in the parlance we're used to, multiple dies in a single emitter.

Yes, that's all wildly unsubstantiated speculation, and may be totally off base from the real reasons. But the point is that there may be very real reasons for using the P7, but like the Acriche they may not be obvious based purely on comparing it's capibilities with the alternatives.

Just my guess anyway.

 

[nein166]

I'm with Goatee, is a P7 upgrade module possible for the HD45?

acourvil great light you put together. I've been wondering what to put in my Aleph 3 since my flupic SSC LE went bad.

 

[LEDninja]

On the multi-LED vs single big LED issue.
Electrolumens has beamshots of his MT4 (4xSSC P4s IMS20 reflectors) vs his P7 (stock Mag reflector).
http://www.cpfmarketplace.com/mp/showthread.php?t=177152
While most posters in that thread like the bright hotspot of the P7, I like the beam of the other one.
I live downtown, do not need mega throw. The only dark spot is an alley with a gravel surface and lots of puddles. The bright spill of a Fenix L0D CE is much more useful in identifying puddles to avoid out to 30 feet. Electrolumens My Little Friend (3x3W) has a much more throw while the spill would only light a puddle as I came right up to it. So a continuous beam of light is better for me than a bright hotspot, a spill and darkness in between.

 

[Isak Hawk]

I wouldn't turn down a hotrod mule