900 Lumen EagleTac Megalight

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I have two elektrolumens, one EDC-P7 and mag P7 mod, and an epsilon ED-P72. They all have good output and I think they around 650-700 torch lumens. I just wanted to make sure that this light didn't have something different that gave it 900 torch lumens.
 
pee10755 said:
I have two elektrolumens, one EDC-P7 and mag P7 mod, and an epsilon ED-P72. They all have good output and I think they around 650-700 torch lumens. I just wanted to make sure that this light didn't have something different that gave it 900 torch lumens.
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I understand D-bin output is 800-900 lumens at 2.8A according to the spec. sheet.

So on average that's 850 emitter lumens.

However reflector losses and loss of lumen output due to heat build up are unavoidable.

Factor these in and you're looking at about 750 torch lumens.

This is about the optimum you can expect for a P7 light and its pretty good in my opinion.
 
easilyled said:
I understand D-bin output is 800-900 lumens at 2.8A according to the spec. sheet.
....
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Yes, but most of the D-bin LEDs will be probably closer to 800 lumens. In fact the D-bin sample tested by jtr1962 was only 765 lumens.

Then you should count with roughly 80% reflector+glass efficiency and you will get around 650 torch lumens. More realistic guess imho 😀
 
Glenn7 said:
I see you like me - go for the throat - when it comes to big bad lights - I have a DEFT now - and FireWater coming - preordered a Mega nano - on the list for a Black Tie 😱 :twothumbs there is one you need to see - its the sunlite 8W :naughty:
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Hey Glenn, what is this Firewater you are talking about? Is it any of these lights?
 
jirik_cz said:
Yes, but most of the D-bin LEDs will be probably closer to 800 lumens. In fact the D-bin sample tested by jtr1962 was only 765 lumens.

Then you should count with roughly 80% reflector+glass efficiency and you will get around 650 torch lumens. More realistic guess imho 😀
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Sorry but I don't accept that by measuring only 1 sample, you can generalise and say the entire D-bin range is under 800 lumens.

I think that unless you're testing a sample of at least 1000, you should accept what the spec sheet says as the standard. 🙂
 
I'm not saying that all D-bins are below 800 lumens. But from the tests of other SSC LEDs it seems that they were usually closer to the lower border. Just trying to be realistic 😉
 
easilyled said:
Sorry but I don't accept that by measuring only 1 sample, you can generalise and say the entire D-bin range is under 800 lumens.

I think that unless you're testing a sample of at least 1000, you should accept what the spec sheet says as the standard. 🙂
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Well, he is not saying that all D-Bins are below 800 lumen. Please have a close look at the data sheets ... especially the part where the influence of Tjunction on the output is described.

The curve shows that "100% relative light output" is reached at 25°C Tjunction (equal to ambient temperature!!!). The internal thermal resistance of the P7 is 3°C/W. Powered at 10W (~2.8A * 3.6V), Tjunction should be at least 30°C higher than ambient temperature ... presuming an ideal heatsink. In real life additional thermal resistance is added by the interface material (thermal paste) and the heatsink itself. So even with a very good cooling on a testbed, the Tjunction of a P7 will be at least 35-40°C above room temperature ....

... and at 65°C Tjunction the output of a P7 is reduced by at least 7-8%. So says the data sheet 😀 ... so a D-Bin measured at 765 lm could easily be 830 "data sheet lumens". And it´s very likely that the majority of all D-Bin P7s are closer to C-Bin than to E-Bin.

I don´t know jtr1962s testbed, but his results are realistic (imho) considered the above ... theory vs. real life I guess 😀
 
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rantanplan said:
Please have a close look at the data sheets ... especially the part where the influence of Tjunction on the output is described.
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In my earlier post (#102) I had already subtracted 100 lumens from the spec. sheet's output for taking into a/c losses
due to the reflector and also due to heat build-up (ie Tjunction).

I'm not saying that this is anything other than a guess, but heat affecting output is not something that I had overlooked. 🙂

rantanplan said:
And it´s very likely that the majority of all D-Bin P7s are closer to C-Bin than to E-Bin.
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Based on what?

I'll be happy to accept this if you can point to some research done on a significant sample size of D-bin SSC-P7s. (ie. at least 1000)
 
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Would be great, if the final version would have a tapped hole between the cells, e.g. for a bicylce handlebar mount or tripod.
 
easilyled said:
Based on what?

I'll be happy to accept this if you can point to some research done on a significant sample size of D-bin SSC-P7s. (ie. at least 1000)
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No scientific sources ... simply common sense :grin2:

First, there are lots of C-Bin, but no E-Bins available. Secondly, I assume that quality of produced LEDs is following a normal distribution, like almost any other production process. The "peak" is probably lying in the C-Bin range ... so there are rather more emitters in the lower half of D-Bin range than in the upper half.

Maybe I´m wrong, but unless I find some serious research, I can live with this assumption. 😉
 
AardvarkSagus said:
Transparent Aluminum in production today:
http://en.wikipedia.org/wiki/Aluminium_oxynitride

Doubt we'll see it in flashlights any time soon. As for Communicators, what do you think a Nextel is? USB Thumbdrive=Isolinear Optical Chip. Palm Pilot/Iphone/other PDA=PADD...Star Trek preceeds technology fairly often actually...
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This is because the people who are inventing all this stuff today watched Star Trek when they were children. You might be interested in watching "How William Shatner Changed the World".

With one very poor exception they didn't use any flashlights on the original series, otherwise we might be measuring output in mega-lumens by now.

Back on topic, I hope EagleTac makes a good holster for this light. So many great flashlights out there, and yet many manufacturers never envision their products being anything other than hand carried.
 
Glenn7 said:
I see you like me - go for the throat - when it comes to big bad lights - I have a DEFT now - and FireWater coming - preordered a Mega nano - on the list for a Black Tie 😱 :twothumbs there is one you need to see - its the sunlite 8W :naughty:
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No need for a Sunlite since I am on the list for a DEFT to hopfully
help satisfy my distance throwing needs 🙂
Once I'm happy that I can throw a blinding spot at 200 meters, I'll
move on to something else :thumbsup:
I still havent decided if I want to keep the open order for Fenix TK40
or go with Megalite.
I think it's best, in the complete absence of reviews and even good
specs, to just wait.
 
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