>>>>>In all honesty I probably wouldn’t even notice the difference (no lux meter).
I have gone from 27k lux with a completely stock HDST to 50+k lux, about 48k lux sustianable, and BOY can I tell the difference.
Why this driver instead of a nan? Well, I had to buy some kind of driver and you don’t know whether something is good or bad until you try ’em. Except for the ridiculous mode system, I think the 4A version is fine. I don’t know about the 5A vesrion. Need to read the BLF thread about it. Made the order when BLF was down so didn’t have the benefit of other’s experiments.
Yes, I have 4 of the Leica coated lenses and they make a difference. Hugely surprised. I’m thinking 10%, but my various versions are getting confusing for comparing specific parts, so I need to sit down and chart everything out (but it’s more fun doing more mods!!).
Also “coppered” the springs (added thick stranded copper inside the springs — thought this was cork sniffing until my test showed improved lux with the copper). Stuck with an 18650. The A8 26650 add-on tube really produced a lux drop. This is probably due to the extra A8 switch, but I don’t want to lose my A8 for the HDST p, so I stuck with the 18650 mod with a coppered spacer. Lost the bolt. The bolt’s resistance (if that’s the right term) resulted in anoother lux drop.
I have only had my lux meter for a few weeks but BOY is it teaching me about output differences. I thought my eye was good at judging diffs, and I am really good at it, but the details that the lux meter turns up are a real help.
I need to sit down and compare all my notes from version to version.
So far I have 5 independent versions working:
1. HDST stock driver with 18650 conversion, plastic lens (about 27k lux).
2. HDST stock driver with U3, 18650 conversion, leica lens (about 32k lux).
3. HDST with U3, leica lens, coppered springs, 2.8 driver (measured at tailcap), 18650 conversion with copper replacement for bolt (about 38k lux).
4. HDST with U3, leica lens, coppered springs, 4A driver, 18650 conversion with copper replacement for bolt (about 44k lux).
5. HDST with XML-2, leica lens, coppered springs, 4A driver, 18650 conversion with copper replacement for bolt (50k+ lux).
I have one more stock unopened HDST that I’m saving for the 5A driver test.
Unprotected batteries SLAY the protected ones in my tests with this light, but that’s no surprise. I didn’t try al of my 300-or-so batteries, but did try a bunch. And surprisingly, the Samsung purple 2800 seem to do best with the 4A driver, beating the panasonic 2900s, which work best over anything I have for the stock HDST driver.
I may try the Nan driver if the 5A driver busts.
But I am pretty happy with the 4A version. I can get 30 solid minutes on high. Light starts at 4.20 volts, 50k lux; ends at 42k lux, 3.85 volts, Samsung unprotected 2800 purple 18650. Like I said, the numbers above may not add up completely correctly. I’m reading from scribbled notes on 10 different slips of paper. Wrote down readings on one component and not on another. Sloppy bookkeeping on my part.