Maybe the evolution of the electric car will prompt an update to battery technology ?
Longer run-times even with the current LED technology.
Alternative Energy 
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yeah
there are thousands of people and millions of dollars working on that…
also the ‘how to store wind and solar’ problem - even bigger than electric cars
with different constraints and goals [for instance the battery does not have be ‘small’.]
One thing we also have to remember about throw is… just because something can be illuminated at great distances isn’t necessarily useful. Because… you have to SEE IT. A small spot is impressive but what does it illuminate? Really, without binoculars, the unaided eye can’t see much detail at all. Then for a wider spot you’re talking a much more massive reflector and LED (s) driven at higher amps… thus a larger flashlight.
But the big thing I believe is the power of efficiency. An LED doesn’t need to put out much more light, but just do it far more efficiently. It’ll be interesting to see if some sort of phosphor hybrid could be developed to achieve that. And while it’ll certainly be many years before we see a 50% increase in efficiency over what’s produced today, the present inefficiency drives the need for better batteries. I’m really looking forward to solid state lithium cells.
Other than efficiency, I look forward to improved power density of emitters and batteries, which allows for smaller optics and body size.
Also, popularization of liquid crystal technology for zoomies.
The end is not nigh at all for lighting efficiency. A more important metric is lumens per watt of heat, because heat is the limiting factor of how bright flashlights can get. For a 100% efficient flashlight, lumens per watt of heat can approach infinity. Here I plotted lumens per watt of heat against lumens per watt, assuming 251 lm/W is 100% efficiency. Lumens per watt of heat grows asymptotically as it approaches 251 lm/W.
Imagine a small 21700 light holding 60A to the LED, giving 55k lumens with no heat. This is possible with a mere 251 lm/W. If you think the end is nigh for lighting efficiency, you are under the illusion of numbers.
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Hmm…
TK was last seen four days ago, but she hasn’t posted anything in months.
I hope she’s doing okay. 
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Yes but then you have to increse lm/mm2 or light density drastically. If were talking about a small 21700 light thats 24mm maybe for the surface are you can use for light emission. If you have a reflector/tir you reduce your 450mm2 area of light emission to 100mm2 of les(thats a very optimistic figure). At 100mm2 thats 550lm/mm2 which is about four times what we have right now and you would also have to increase efficacy by a lot too of course. Im not seeing we wont see extreme figures in the future, but its going to be a long jurney. Still excited for my 14500 light with 10000 lumens tho in the year 2100 if humanity doesnt bomb or reset itself before that.
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At my age of 80 now I am afraid that I cannot wait till 2100 AD! 
I would note though that in conversions nothing is ever 100% efficient. Always some losses. In electrical and electronics the most efficient device I am aware of is the transformer which can approach 98 to 99% efficient.
I’ve just had to focus on other things. Working at my desk hurts my spine, and I can’t do much flashlight stuff anywhere else. Have also been generally trying to brace for impact due to impending, uh, political changes. It seems likely that things are going to get pretty bad.
But this means I’ve been a terrible open-source maintainer lately, and I really should do something about that. There’s a lot to catch up on.
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I sincerely hope you stay safe. I already have so many friends suffering over there and its just the beginning of the storm. You shouldnt care about the open source stuff and i dont think anyone here cares about that over your health and safety.
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Wishing you all the best. Take all the time you need. You’ve already given more to this community than pretty much anyone else.
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I also similarly need to get myself back into things. Been very burnt out for the same obvious reason, plus some health issues of my own, not to mention the fact that right now most of my stuff is in boxes so there’s not a lot I can do in terms of anything that needs development hardware. I was only just starting to fully recover from a period of unemployment when the event happened too. Looking forward to some more activity on the project again so I can get myself back in a bit too though. I’ve got a few pull requests that I’ve tested and been running for a while, also a few others I reviewed, I think having a somewhat structured review system for PR approval would streamline development a lot. I’ve definitely stopped thinking about new features recently, vs just maintenance, and I’d like that to change again.
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