Re: Hello, it's me again, now with a 1.7 watt Fenix driver.
Hello,
I've spent a great deal of time comparing the modded Fenix I received from MM to many other lights, most critically with stock L1p v2.5 and L2p. The light I have has an S-bin Lux III and Eric's high output driver. The synopsis he delivered of my preliminary findings is spot-on (bad pun). The spot size is almost double compared to the stock L1p but the intensity is similar. The projected spot is a result of the LuxIII's slightly different positioning inside the reflector. I was expecting a larger brightness difference but MM relayed to me that the only LuxIII he had at the moment was the S-bin. A TWOH would have made a striking impact with its better efficiency and lower Vf. Since this was just a preliminary step its shows very good promise and the driver proved capable (and had a HUGE suprise in store for me, more on that later...). There was a little fluctuation in the light level on the MM at first, but a little snugging of the LE to tighten up the ground resolved that issue.
There is also a 2-stage switch mod on my review unit, an unexpected bonus, offering a very usable low level to offset the high level's shorter than stock runtime. I did most of my comparisons with Rayovac IC-3 2000mAh NiMHs, 2500mAh Sanyos, and Energizer e2 L91 Lithium AAs. Measured current at the tailcap: stock L1p was 980mA-1.030A with NiMH, MM version 1.180A-1.300A with NiMH. Clearly the MM driver was pushing the LuxIII harder because it generated noticeably more warmth in the head than a stock unit, especially after 15 minutes or more is was quite evident but not bad by any means.
Runtime (on NiMH) was shorter, as was expected, at about 45 minutes full brightness tapering off slowly until about 90 minutes, where it began "moon mode" . The stock R-bin Fenix trounced it completely, giving an incredible 110 minutes full brightness and tapering very slowly till the 3 hour 20 minute mark, finally hitting moon mode with an exhaused NiMH cell. Runtimes are longer with Lithium AAs but I had a shortage of the cells to do a proper full-on runtime test with them.
I used a Meterman LM-691 light meter for lux readings at 1 meter and got the following results: stock L1p on NiMH: avg 480 lux (530 on Lithium AA) compared to 580 lux NiMH (590 Li AA) for the MM Fenix on high level.
Then came the huge suprise. I tried the MM driver Fenix with a 14500 3.7V Lithium Ion rechargeable cell. And my jaw just dropped at the results. 1280 lux at 1 meter, more than double the output with NiMH AAs. In short, the Fenix began to live up to its "bird of fire" namesake and cranked out an incredible amount of light. A huge WOW factor here! I was really taken by suprise as it had been quite a long while since the output of a single LuxIII light made my eyes go wide. The driver handles the extra voltage without a hitch, pumping 1.890A from the cell and generating quite a lot of heat in the process. It outgunned a McLux PD TWOJ and even exceeded a U-bin Orb Raw! Its beam profile was very similar to a Raw, a fairly large center spot with even intensity and plenty of useful corona light with a nice even transition. But on a LiIon it was brighter overall than all the single LuxIII lights I could throw at it, except the giant killer McGizmo HD45 running a UX1K @ 950mA. Brighter overall than McLux PD, Lioncub, KI, and HDS U85! Of course runtime is short, limited by the heat generated on high level, but it handily outlasts the U-bin Raw while being brighter! The neat thing about this is on low level, output is almost identical to a stock L1p, although the runtime is still noticeably shorter.
I'd have to summarize by announcing that Eric Miller's driver circuit is indeed successful and drives the LuxIII quite nicely, with the unexpected bonus of being able to transform the little Fenix into a flame thrower with the addition of a 14500 cell at will. The major downside is the loss of runtime compared to a stock L1p, which to me is one of its key selling points, the ability to run a HECK of a long time on a single AA. What we have here is a hotrod Fenix that has the potential to be significantly improved with a premium binned emitter and some fine tuning of drive level.
As a mod, its functional and effective, albeit geared towards maximum brightness. For me personally, a stock L1p is such a nice well balanced package offering stunning runtime that I would be reluctant to give that up. With the MillerMods driver, runtime is comparable to stock on low level, and superior in brightness and a much bigger spot (almost 2x) on high, making it a worthy contender. Whats REALLY cool is like nitrous oxide in a car, on demand you can throw in a 14500 cell, amaze your friends and confuse your enemies with an astounding amount of output from a single LuxIII and click down to low for stock L1p light levels. Final verdict for me (dominated by lust for brightness) is a thumbs up, with the caveat that some adjustments should be made to the levels of the unit I have. Of course MillerMods can accomidate any reasonable request, as I have opted for a lower low level and different emitter. I plan on having 2 of them, 1 with an overdriven stock R-bin and one set up for rechargeable LiIon and likely a UX1K or TWOH.
Is this basically a boost circuit? Is the rundown curve going to look like the battery discharge curve? What happens if you throw in a lower Vf LED? Does the current go up or remain largely the same? 10 Ohms is 175 mA from the cell, that drives the LED at what, 50 mA?
