I got my UF-1504 and installed an XP-L HI V2 1A emitter and FET driver from mtnelectronics. First, I made some external modifications. The big square protrusions on the body and tailcap make it uncomfortable to hold, so I removed them. I don’t have access to a lathe, so I used a saw, dremel, and file. It looks a bit rough, but it is now much nicer to hold in the hand, and I can now comfortably use an overhand grip, which was very uncomfortable in stock form. I also attached a belt clip to the head.
I then went about searching for a suitable lens to use as a pre collimator lens. I decided that the included threaded retaining ring would make a great height-adjustable lens mount. I decided on a 15.3mm diameter double convex lens with 7.6mm FL from anchor optics. It does not have AR coating. I wanted as strong a lens as possible and there was not an AR coated lens available that was as strong.
I drilled out the retaining ring to 12.5mm, then used a dremel and file to enlarge the ID to ~15.5mm. The lens just fits inside. I put small dots of epoxy around the perimeter to secure the lens to the retaining ring.
Here it is installed in the pill.
I adjusted the height of the pre collimator lens so that the cone of light just filled the main lens, as I described a couple posts back.
With a purple Efest 4200mAh 26650 cell at ~4.16V OC, I measured 5.3A bypassing the tailcap. I measured my ammeter resistance to be ~35mOhms. I took before and after pictures and lux measurements. The exposure settings were not controlled, so the pictures should only be used to compare the beam sizes. I recently bought a Tondaj LX-1010B which I used for the lux measurements here. Note that this meter reads high for cool white tints like the 1A. From djozz’s excellent measurements here
Stock light without pre collimator lens.
11,800 lux at 6.05m: 432,000 cd
approximate beam size: 20cm x 20cm
very approximate lumen estimate= 0.2m x 0.2m x 11,800lux = 472 lumens
With precollimator lens adjusted so cone just fills main lens.
8,600 lux at 6.05m: 315,000 cd
approximate beam size: 33.5cm x 33.5cm
very approximate lumen estimate= 0.335m x 0.335m x 8,600lux = 965 lumens
For this shot I adjusted the precollimator lens slightly closer to the LED, so that the light cone just overfills the main lens. I will lose a bit of light, but will pick up some cd.
9,800 lux at 6.05m: 359,000 cd
approximate beam size: 30.5cm x 30.5cm
very approximate lumen estimate= 0.305m x 0.305m x 9,800lux = 911 lumens
I’m pretty happy with the result; about double the beam lumens with not too bad an intensity drop. It could be improved by using a suitably strong precollimator lens with AR coating. I also bought a 15mm diameter plano-convex lens with 15mm FL and AR coating. I may try this lens in the future to see how it works in the light.