Ok - finished the Y3 mods. Here's some details.
20 mm square, 1.15 mm thick, MaxToch star, penny for size comparison, and originals:
MaxToch 26 shown positioned. I marked a spot for drilling a hole. Original holes are not aligned well:
After the hole was drilled. Used my cheap drill press, ala comfy:
I cut and sanded down the stock LED alignment piece. 1.23 mm thick originally:
Sanded down to 0.75 mm. Used a pad of 100 grade paper, and rubbed the part on it:
Shown here with original pieces:
I reflowed the emitter (XM-L2 U2 1A) and the 20 mm copper shim in one step. Used solder paste, and frying pan, monitoring the temp with a hand help IR temp probe. Surfaces sanded to 2000 GRIT. When installed, I used GC Extreme thermal grease between the shim and shelf:
Backside view. I did more sanding after this pic, before mounting it, to remove that oxidation from the heat:
Though I did drill and tap holes, they didn't come out aligned up well, so didn't use screws - I could have widened out the holes in the MCPCB and got them to work. No worries with any possible shorts to the reflector. Nice low profile, and beam looked well focused compared to a stock Y3 beam - tighter hot spot. Also, the black hole doesn't appear til about 2" from the wall - nice for a Y3.
This has the stock driver with one R100, measured 3.16A at the tail on one KK cell, and 2.60A at the tail with two KK cells. Hhmm - the 26700 did not work -- seems too long. I thought all the Y3's worked with the 26700 - apparently not.
Results:
On KK 4200, 3.16A tail: lumens - 1,170 @start, 1,139 @30 secs, throw: 79 kcd taken at 5m
On two KK's, 2.60A tail: lumens - 1,428 @start, 1,380 @30 secs, throw: 95 kcd taken at 5m
Note: all my lumens and kcd measurements are "my own" taken on an older LX1330B meter - kcd taken indoors and lumens in a PVC constructed lightbox, accuracy can be freely debated (CYA all the way...)
Conclusions:
- note the 3.16A is sort of low, lower than I tested last night (3.6A) - can't explain, but used a different LED/MCPCB
- 2.6A at the tail for 2 cells is maybe 4.6-5.0A to the LED I'm guessing (totally guessing).
- this is with a UCLp installed, driver and tail spring copper wired
- results using 2 cells is pretty awesome - lots of light, great throw, but the LD-1 driver in my XM-L2 U2 1D Y3 still does better (higher amps, 111 kcd)
- total height of the MCPCB and copper shim is 2.63 mm, so about 1.15 mm increase. This was need to compensate for the reduction in the LED alignment piece, and the drop in height of the MaxToch compared to the stock MCPCB (about 0.5 mm less). I think the height/vertical dim turned out well - can full tighten the bezel and everything seems snug.
- I'm impressed it holds output pretty well in the first 30 secs - not much drop there - I've seen far worse.
- I like it, but don't like the stock driver UI - would rather have full control from the side switch, like the LD-1 driver or my (and others) custom drivers.
- Better mod upgrade would be a piggyback'ed BLF17DD with custom firmware, but then you lose the multiple battery capability.
Hope this answers some questions and gives you a better idea of what a mod can do for this light.
Copper shim bought in this nice assortment pack: ebay-45pcs-Laptop-GPU-CPU-Heatsink-Copper-Shim-20mmx20mm. Comes to about 25 cents each.