I’ve been thinking about LED efficiency lately and how it’s going to effect the future of flashlights. Most of the cutting edge high lumen lights end up being thermally constrained (D4 anyone?). Taking the D4 as an example, it runs at something like 24 amps which, while awesome, is really inefficient. We’re talking like 15% efficient (60lm/w). That means that the other 85% of the energy being pulled from the battery is just turning into heat. The D4 is running at the 6 amp mark on this graph:
It’s kind of sad looking at it like this, but there is something interesting to be seen here… All the way to the left, there are efficiencies approaching 200lm/w. These kinds of efficiencies will eventually be available for the higher currents as well.
So what can we expect to see from more efficient LEDs?
Less heat
More Light
The two factors end compounding on each other and something really cool happens:
So what this is showing a model of a flashlight that can only absorb 100w of heat. This is about what the the Astrolux MF-01 is putting out. Take for example, when LED’s that can produce 200 lm/w at high currents are available, we can expect to see MF-01 size lights putting out 40,000 lumens.
Well obviously if the light uses a constant 100W, the more lumens it puts out the higher it’s efficiency will be…
But this is not how physics works in the real world.
The first graph is how they work.
More lumens -> less efficiency.
It will be a very long time before you actually see both high lumen output and high efficiency.
Your post is basically “in the future we will have 0 emission vehicles and life on mars and flying cars!!”
A bit optimistic and far fetched IMO.
We will probably never live to see 60k lumens at 250lm/watt, at least not from a handheld device.
The second graph isn’t showing a light that uses a constant 100w. It’s showing a light that puts off a constant 100w of waste heat. The remainder of the input energy is given off as luminous energy. If you look at the graph below, and consider it in conjunction with the second graph in my previous post, perhaps it’ll make a bit more sense.
The distance between the red and blue lines is equivalent to the energy emitted as light.
The key idea here is that with greater efficiency, you can actually create a light that uses MORE power, while not improving the ability to expel heat.
As far as the development timeline, I wouldn’t be so sure about not seeing this in our lifetimes. Check out these:
