100 Watt 10,000 Lumen LED 'DayMaker' Flashlight Build

[jayrob]

You lose half of your light to either side of the lens to start off with.

The same physics apply for LEDs. A bare die is basically a 1 1/3 inch "beam" with a divergence of ~160 degrees. Expanding 3x to 4 inches cuts divergence to ~53 degrees. If you're more familiar with radians That's about 1 radian (1000mRad).

The emitting area is the limitation here. You cannot tame it. Physics will win EVERY time.

With the normal sized LED's that I have worked with such as the XML, the larger the reflector, the better the throw. (in general)

I realize this thing is a huge emitter and will have a wide output no matter what, but I'm thinking it can have better throw with that larger reflector and lens.

Worth a $10 dollar experiment for sure...

 

[Benm]

You can trace rays to see what happens for a give led and reflector or lens setup.

The output from the LED could be about a radian wide, i guess it varies among them.

In any case the die size is so large you'd need a huge reflector/lens to get a reasonably narrow beam out of them. In such cases it would be more realistic to actually use twenty 5-watt single chip leds each with its own lens.

Such an assembly works well in the medium to long throw range since the beams will then overlap, even if there are 20 of them.

For the 100 watt LED this could sort-of be done with a microlense array directly on the LED, though i'm not sure such things are commonly available, nor how tightly they focus the output.

 

[jayrob]

Got a second lens today so I could experiment with sanding the back side...

Wet sanding did not work too well so I put a very light etch with my sand blaster:

The yellow ring is now gone... (Spot on the wall at 4' distance)

Stock lens:

Etched lens:

Adding to OP...

 

[Benm]

Seems like a more even output pattern, but also a lot wider, or is that just an artefact in the photo?

 

[jayrob]

Seems like a more even output pattern, but also a lot wider, or is that just an artefact in the photo?

Yes evens it out and also makes it wider.

Wider but that takes a little away from the central brightness because it spreads it out...

 

[Cyparagon]

Why use a lens in the first place if you want to scatter the light? Use a window.

 

[jayrob]

Why use a lens in the first place if you want to scatter the light? Use a window.

Yeah just a nice dust shield as long as it didn't block the air flow coming through the tube.

Like a normal flashlight lens same diameter so that it can just fit right in the existing lens mount...

 

[plag]

Wow! I want it!! How long does it last on one charge?

 

[Cyparagon]

14.8V at 10Ah is 148 watt-hours. With a ~80% efficient boost converter and adding misc circuits, that would mean something like 60-70 minutes in theory. The measured figure of 8.2A would mean 73 minutes, but that current draw will climb as the battery drains.

 

[plag]

14.8V at 10Ah is 148 watt-hours. With a ~80% efficient boost converter and adding misc circuits, that would mean something like 60-70 minutes in theory. The measured figure of 8.2A would mean 73 minutes, but that current draw will climb as the battery drains.

So how long will this setup work with 100% output(8.2A)?

 

[jayrob]

So how long will this setup work with 100% output(8.2A)?

The driver actually does slightly drop out of regulation as the supply voltage drops during discharge...

It's not enough to really even notice though. By the time your down to recharge time, it's still giving about 2.4 Amps to the emitter/s...

But it's still so bright at that current that you really don't even notice any difference...

The good part of that, is that the battery will last longer.

I would say probably about and hour and a half...

My second version is 3 hours. Using a 6S 12 Amp hour pack at over 25 volts full charge means less current draw to boost voltage demand at 3 Amps...

See here:
Version 2