Welcome. It is great to see a variety of professionals seeking advanced lighting technologies. Could you tell us what budget you wanted to work with? Even though I love DX/KD for their selection and low prices, I think that so you can truly be happy with the finished product without any future reservations from using LED products, you should spend a bit more.
Well, if that is truly a Cree brand optic (like the first that were available), then that seems to be a good choice. I have little experience with optics and Cree XR-E emitters (I worry about square-looking artifacts). So if you cannot find suitable optics, there are great reflectors out there that work well with the XR-E. I agree that asheric lenses, when slightly out of focus, would work swell for your application! They cast virtually no spill, and provide a very tight, but even beam. It may look ugly on a wall, but works great when actually being used. I believe saabluster would be the proper person to ask for more info on different sized aspheric lenses!
DX does sell some lenses that are made of plastic and are lightweight. The quality of the plastic lenses will be pretty decent, so you probably will not need any made of glass.
As for the LED emitter, maybe you should shop around a bit first. Even though it is a XR-E Q5 WG emitter, you may find it to be too bluish compared to the warmer whites that you desired earlier. WH and WJ was the warmest of the cool white bins. I am not sure if you would enjoy the slow service (the shipping) of DX, either. There are several sources for other XR-E emitters around here at the CPF. Just ask (as I am not sure of the latest sources).
I remember reading a bit about neutral and warm white emitters, so I found those links for you...
Mudman CJ took some shots of an incandescent light source versus various high CRI emitters here:
https://www.candlepowerforums.com/threads/211911
saabluster took some shots comparing his WH cool white XR-E, his 5A XR-E, and his 6C MC-E emitters:
https://www.candlepowerforums.com/posts/2654418&postcount=269
To get an idea how the warmer of cool whites compare to neutral and warm whites, I stitched together two tint binning charts that DFiorentino created from X and Y data in
this sticky thread. I hope he does not mind. They were scaled differently, and I did not have the original excel files, so I re-sized them and combined them using PSP8...
Notice that the WH/WJ tints overlap the 3A/3B tints slightly. With a neutral white (with a bin code from 3-5), you will be closer to that BBL line. The WH tint is pretty broad and can extend into the greens a bit.
Well, I am not sure where to get a neutral white or warm white (besides Cutter), so maybe you can check with mudman or saabluster as to where they got their warmer emitters.
As for batteries: get the best. I am weary about even using those protected li-ion cells from DX. The protection circuitry could be set incorrectly, which can be a bad thing. Those cheap, Chinease cells are also often over-rated, and you can never be sure if they will work at all sometimes. I reccomend AW's li-ion cells (found on the CPF). He sells a range of sizes, and they are of the highest quality! They are not that expensive, either. Plus he stands behind his cells confidently. The capacity rating of his cells are right on with what you will really get, I believe. If you have the external pack located on your hip, then you could use higher capacity cells. His largest cell is a C-sized cell that sports a 3300mAh capacity. On the other hand, if you want to stay away from li-ion, then buy Eneloop brand AA cells (3 in series should work -2 may work at low current levels). Walmart sells Duracell rechargeables that are the Hybrid types. Look for the ones with a white color surrounding the (+) button. Those are from Japan and have a better quality than ones with a black colored surrounding. There are other brands of high quality hybrid AA cells around here as well. Again, just ask around!
I would reccomend that you use some sort of driver circuit to regulate your current output. However, if you will run the emitter at below 100mA from a li-ion cell, you may be able to get away with DD with a resistor to reduce current. If the power is low enough, you may be able to use a linear variable resistor to dim the LED as needed. A cheap and simple linear voltage regulator would also work (using a potentiometer to dim the LED) since the operating efficiencies are not as dramatically important with these low current levels. Either way, you will get some great battery life if the currents are this low.
LEDs are very efficient, so the amount of power required is so much lower that what you may be used to with a light bulb. Well, due to the efficiencies, I think that with such a narrow beam, currents above 100mA will create enough light that can be uncomfortable for the patient. With several hundred milliamps, it is possible that you could do some damage as well
. That would sort of go against your entire profession, wouldn't it? I say that once you get your LED and optic set up, experiment with current levels to see which provides the correct amount of lighting.
-Tony