Here is my basic understanding of what affects output and throw capabilities. I did some general estimation in here.
1) Current supplied
So for starters, we must think battery. From what I can tell, the battery with the maximum output for a AA is the Energizer Ultimate Lithium L91.
datasheet: http://data.energizer.com/PDFs/l91.pdf.
It states clearly that the max discharge current is 2A (at 1.5v). Factor in ohm's law and around a ~3.3v forward voltage for your average LED, we are really only going to get about a max constant discharge of around 900 mA output at best.
The next logical step is to minimize the amount lost through the boost converter circuit. I don't know what a realistic expectation is, but I am ball-parking 85%. We're down to about ~760mA reaching the LED now. (Most AA lights can fit a 14500 lithium, but I can't reliably find any datasheets that come close to the output of the energizer).
2) LED efficiency and surface area of the emitter.
From what I have seen, and correct me if I am wrong, the CREE XRE appears to be the smallest surface area, and this dramatically improves throw all other things considered equal. Since it has a 1A constant current capability, the L91 AA will not be able to overdrive it at its max output. While it is not as efficient as some, most others have a much larger surface area (XML) that cannot be focused for throwing in a small package.
3) Optics
I have read that glass optics tend to have less absorption than most plastic molds. Other than that, the optic needs a surface area large enough to capture the majority of the light and collimate it into a tight beam.
Am I generally correct here? Anything you can add would be nice. I want to make sure my understanding is right before I start dropping money on fabricating.
1) Current supplied
So for starters, we must think battery. From what I can tell, the battery with the maximum output for a AA is the Energizer Ultimate Lithium L91.
datasheet: http://data.energizer.com/PDFs/l91.pdf.
It states clearly that the max discharge current is 2A (at 1.5v). Factor in ohm's law and around a ~3.3v forward voltage for your average LED, we are really only going to get about a max constant discharge of around 900 mA output at best.
The next logical step is to minimize the amount lost through the boost converter circuit. I don't know what a realistic expectation is, but I am ball-parking 85%. We're down to about ~760mA reaching the LED now. (Most AA lights can fit a 14500 lithium, but I can't reliably find any datasheets that come close to the output of the energizer).
2) LED efficiency and surface area of the emitter.
From what I have seen, and correct me if I am wrong, the CREE XRE appears to be the smallest surface area, and this dramatically improves throw all other things considered equal. Since it has a 1A constant current capability, the L91 AA will not be able to overdrive it at its max output. While it is not as efficient as some, most others have a much larger surface area (XML) that cannot be focused for throwing in a small package.
3) Optics
I have read that glass optics tend to have less absorption than most plastic molds. Other than that, the optic needs a surface area large enough to capture the majority of the light and collimate it into a tight beam.
Am I generally correct here? Anything you can add would be nice. I want to make sure my understanding is right before I start dropping money on fabricating.
