Full regulation has typically meant reduced output, our direct drive lights allow all a cell can give with the caveat that output diminishes with the cell. Full regulation also typically comes with a higher price tag. In larger lights that can house a driver with room for the components full regulation is more feasible, but the output question again comes into play. For this you might look to Nitecore and Fenix and such, but expect to pay premium prices…
OK, thanks
Thanks
I get it now. Thanks for that clear explanation
R.I.P. amber aux leds.
Is there a list of how bins translate into Kelvin ranges?
ANSI white color space chart. Or look through the manufacturers’ LED data sheets, which use the same color space but may sometimes change the names of the bins.
Regulation tries to maintain a consistent amount of output at any given level without being affected by the amount of charge remaining in the battery. So if you select a level that outputs 150 lumens you will get that with a full battery and you will continue to get that down the point where the battery is nearly dead.
Some lights are fully regulated, but that does normally limit their maximum output. Emisar lights are regulated up to a certain level, but can go far above that if the battery is in reasonable shape. A FET circuit allows the light to be driven as hard as the battery will allow. 7135 chips can each typically drive somewhere between 120 and 180 lumens of constant output. The D4S has a FET and 3 7135s, usually abbreviated as FET+3. That allows it to support very high outputs, but also gives it regulated output up to a bit over 400 lumens.
Just to complicate things, some lights, like the D4SV2, have an additional 7135 that is used somewhat differently. It is used to drive higher regulated output, but it is also used to support lower output in moonlight mode. The D4SV2 is FET+3+1, giving it a very low moonlight mode and a regulated output up to over 500 lumens.
Note that the 7135s do not do anything to boost the maximum output under FET.
Probably more than you wanted to know. 
I’m still trying to figure out drivers myself.
Thanks, that’s very helpful, but I’m frustrated that both XPL Hi and SST 20 have no choice midway between 6500K and 5000K. I have a wonderful old Thrunite TC20 (1x XHP 70.2) that is somewhere I would guess around 5700K that is really perfect for my use. Why are those D4S LEDs limited to those particular Kelvin temperatures; are there really no choices in between ?
Not at all; really informative, thanks.
XP-L comes in ~4875K, ~5175K, ~5525K, ~5900K, ~6300K, ~6700K, etc… So the desired color temperatures exist. But they are not always available inside flashlights.
Usually manufacturers have to buy reels of about 3000 LEDs at a time, so it is not feasible to offer every possible tint bin. So they pick a few which span the white spectrum. Doing the math, the Emisar D4 comes in 3 shades of XP-L HI, 4 shades of SST-20, and 1 shade of Nichia 219C. So 8 types of emitters. That’s about 24,000 LEDs total, ordering in reels of 3000. Divide by 4 LEDs per light, and that works out to 6000 total lights. This can be shared across models though, so it doesn’t have to be all D4 or all D4S or all D1 or all D18. That helps. But still, Emisar essentially had to commit financially to selling about 6000 lights in order to offer 8 flavors of LEDs. Adding more in-between tints would increase the costs without really incresing the sales much, and Emisar would probably be stuck with a bunch of extra LEDs which didn’t get used.
They generally can’t buy in smaller quantities unless something like this has already happened and some other company is selling extra stock. Plus, it’s difficult for manufacturers to guess accurately how many of each version to build, and difficult for retailers to guess how many to stock. So the choices are limited.
YOU, on the other hand, are not limited to reel purchases and are free to pick up your favorite tint from Mouser or Arrow or Digikey or Kaidomain or Cutter or anywhere else you happen to find them.
I could solder a speaker wire most of my life, and yet I learned to modify a flashlight to my liking. I am pretty sure that if I can then almost anyone can. Seriously. My eyesight is not good, I have an ongoing fight with stress that causes intense muscle spasms, really not at all a likely candidate for soldering small components, and yet, I’ve managed to build a few lights over the past several years.
Yes, it’s intimidating to begin with but like the movie says, “Anyone Can Cook!”
Impressive, but I’m not sure that almost “anyone” would have the consistent motivation to learn and practice these skills. I will probably get Vinh to mod a D4S using some of the LEDs you mentioned. Thanks for that info.
We have people here in their 70’s and even 80’s… a lot in their 60’s. But of course, if the fates have dealt a hand that doesn’t allow fine motor skills then indeed a punt is in order. Quite a few folks here will mod a light for a fellow member, many at cost of parts. Vinh’s fancy Corvette didn’t come free and neither does Vinh…
(dang, the 60’s is looming nigh and it just don’t seem possible! Age is, many times, far more than the numbers on ones birth certificate… life has a funny way of throwing completely unexpected curve balls.)
Now I understand. Thanks
I’ve had some curve balls hit me recently, but with the right attitude you can cope with (almost) anything. Speaking of Corvettes, we had a 1951or ’52 Hudson Hornet. It was built like a tank but the V6 (might have been a straight 6) moved it right along.
Oh to have that car now…
My first car was a ’51 Chevrolet Custom DeLuxe with straight 6 and 3 on the stem. Armstrong power steering and 460 AC. 
Wouldn’t move out, vacuum windshield wipers truly sucked, but I’d still love to have it now… 6V battery and tube AM radio were also a poor combination…
To activate manual memory, turn the light on (1 click), then go to the brightness you want (hold button), then click 5 times to save that brightness. Afterward, 1 click from off should always return to this brightness.
To go back to automatic memory, turn the light on, then do 5 clicks… but hold the last click for a second until it blinks.
To configure what happens in momentary mode, first go to the mode you want to use in a momentary fashion. For example, for a momentary strobe, first go to strobe mode (3 clicks from off, but hold the 3rd click for a second… and then double click until it gets to the strobe you want). Then turn the light off (1 click), and then start up momentary (5 clicks from off).
Somehow it just makes sense when you say it.
Less than a minute of reading and not only do I know that I want manual memory, but I know how to do it. Even better, I know how to turn momentary into an instant strobe mode. 