I wonder what will come along to improve on the performance of this LED in the big maximum range high lumen throwers ?
I would hope it will be efficiency. In a perfect world there would be no heat created from the LED because that is wasted potential energy.
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Due to the design limits probably none. Its a 3v led with a huge LES and low thermal resistance, it’s pretty much optimized as much as it can be currently. The specs don’t lie: its capable of 5000+ Lumens and easily throws 600+m out of a 45mm reflector. But it gets hot fast, requires very high drive current.
Will it be possible for a new LED to top this one in lumens, throw, less heat sometime in the fairly near future ?
Warmer CCT (4000k) with good tint, maybe high CRI.
Yes lumens/lux will be lower, but it would be a be top performer compared to other emitters with similar colour temperature.
Depends on “fairly near future” and “top this one in lumens, throw, less heat”.
Appears that the incremental improvements in LEDs is smaller compared to maybe 5+ years ago.
Most improvements will likely be on paper, 5% improvement in all the above… not visible to the eye.
Most lights are fairly easy to upgrade if new LEDs appear.
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Thanks, I figured the point of diminishing returns was pretty well in effect at this point.
Not in the near future unless advances can be made with LEP technology, which is still fairly new to flashlights. (Since 2016. LEDs have been around in flashlights for almost 20 years). For current CSP (flip chip) designs and mainly improved efficiency at higher power outputs is my guess. The Chinese companies are ramping up and releasing new LED designs so maybe they’ll be the frontrunners in new tech?
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The lights need massiv heads or active cooling besides good, true temperature regulation. The regulation of the T90R is among the best I’ve ever seen. Start cooling it and the power increases. This beast with a fan would be really nice.
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Just the fact that there’s well over 1000 lumens between the lowest flux bin and highest means it isn’t completely optimized.
Surely that’s more of an artifact of how we measure lumens than potential efficiency gains?
Perhaps I misunderstand the concept of lumens and efficacy. In my head, the more green a light is, the more “human eye visible light” it puts out for a given input power.
Eg. Pure green LED will wipe the floor with any white emitter because lumens are measurment of “visible light”, and human eye is most sensitive to green.
Conversely, a red LED will be least efficient as for same power input the human eye is not very sensitive.
Edit to add: I thought about it some more and guess you’re talking about output bins within same CCT Vs bins between different CCT? So my point doesn’t quite stand.
I’m more interested in what actually defines the difference between a 5000 lumens XHP70.3 and a 5000 lumens SBT-90.2.
- Is the difference in throw/flood solely decided by the LES?
- in very rough estimation a XHP70.3 will need around 6V 8A for 5K lumens, and an SBT90.2 will need 3V >20A. What makes this difference in efficiency?
- Why are we mostly running emitters at extreme currents and at lower efficiency instead of multiplying the # of emitters in an efficient way ?
Maybe it isn’t cost efficient (total LES mm2, reflector) and hard to do in a thrower concept.
Many of us, including me look at a LED and say “emitter goes brrr” without really knowing what is going on.
**I want make a list or measurement unit of perceived brightness vs efficiency.
Take for example a 519A (@djozz 's measurements):
- It will take around 3V6A to max it out at 1250 lumens
- it will take around 3V3A to reach a more efficient peak at 800 lumens.
Which is half the amps, half the heat, but not half the perceived brightness. Is 1250 vs 800 worth it then?
But still most of us run a 1 x 519A at 6A, to get the maximum lumens but don’t consider the negative consequences. This is where quad lights come in.
4 x 519A in parallel at 3V6A will produce a total of 2400 lumens vs 1250 lumens from 1 x 519A at 6A. That is almost double the efficiency.
Then we take in driver efficiency and heat in the equation, and a boost driven 2s2p 6v setup will be far more efficient than a 4p 3v CC
If we measure efficiency vs perceived brightness, I think we can really make some steps towards a brighter future.
Not disagreeing, but as a thought experiment: let’s assume people need lights to look at stuff.
For this example, the stuff is 30m away. The user will want a certain amount of light on the target to consider it lit up.
A floody light will have to achieve this with overalls higher lumen output, whereas a more throwy light can achieve this with less lumens.
Generally speaking, multi-emitter lights are more floody.
When you say perceived brightness, do you mean lumens or lux?
I might have ranted a bit but;
Perceived brightness:
Let’s again call upon the 519A example
- 1250 lumens in one light
- 600 lumens in the other light
The first light will be brighter, but not double as bright as the second light. But it will use twice the power and generate twice the heat. Is it worth it?
We could quadruple the emitters in the second light and get the same heat generation and power draw as the first light. But this time around 2400 lumens @ max.
So we can theoretically lower the output of the second light to ~ 1250 lumens and both lights will have the same PERCEIVED BRIGHTNESS at very different efficiencies.
If we could then optimise the beams to look somewhat the same (for example 4 x 6° TIR), then the 2nd light is the better choice everytime?
The optimising of the beam is the biggest issue atm.
1 x SBT90.2 @25A will never look the same as 4 x SBT90.2 @25A (6.125A/emitter) because of a bigger total LES, and the need for smaller reflector per emitter. But it will be more lumens though.
I want to see more lights being optimised to work at the peak efficiency curve of the emitter instead of going all out.
That’s a good point.
I was thinking along the lines of like, if the datasheet is telling the truth and only the two lowest flux bins are available for order, the other half dozen higher ones are sent out “at Luminus’ discretion”, that doesn’t sound the process has been fully optimized for brightness yet. There’s some room to improve in there
Even more than twice. Becomes less efficient as it gets brighter.
The catch there with the sbt90, or all Luminus’ emitters really, is theyre really green at lower currents and don’t look good until the high end lol
Well as far as I can tell, SBT90.2 are the hottest thing at the moment. I have the idea that most manufacturers are happy IF they receive those emitters, and will start talking about bin’s when the market isn’t so hectic anymore.
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It might be different already. Datasheet could be out of date. Or that rule might not even apply to everyone, idk. Prices seem to be going down and there’s clones popping up. They aren’t as good but they’re a lot cheaper and not half bad
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The price of Sbt90.2 has stayed pretty consistent, around $40 US. The clones from China like the GT9090 are around $12 US or something like that. Yes, cheaper, but not as good. Tint wise, the Chinese ones are worse (more cool white-shifting very cool when driven hard) and less efficient so they don’t ger as bright. I think its around 85-90% of the real Sbt90.2 per my measurements.
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Thanks for that info!
I didn’t know hardly anything about the GT9090 until now. 
$30 from convoy now. (and Neal) Closer to $25 if you buy a handful.
The clones of course aren’t as good but could be a factor in driving the price down lower
This is the King of thrower LEDs. It better be a substantial improvement.