TK's Emisar D18 review -- 3x18650 photon grenade

So the moonlight (low) mode seems to be much lower on paper than the D4 and D4S, is that right?

Pavio, I am not so young anymore. Most of my life a flashlight got dim as it’s cells grew discharged, so to me that is how it is supposed to work. As my work with the flashlight progresses, I am constantly reminded of how much longer the flashlight will work for me by the ever decreasing output. I can easily judge when to take a break and replace cells. Being very forgetful by nature, all my life, when I am involved in work I have little time sense, so the flashlight itself can help to remind me to take a break, get a drink, food, whatever.

I also do not like pulling more amps out of a nearly dead cell. The regulated drivers do this to maintain brightness as the cell discharges, the lowest current is pulled from the most capable charge level, the highest current is pulled from the least capable charge level. I do not like this. I do not like subjecting this (what I think of as abuse) behavior to my cells. I would rather hammer them down with massive current draw right from the beginning. :slight_smile:

And like Jason said, the regulated driver is not capable of maximum output from the beginning. I like Turbo. Not quasi high. Call it a Texas thing. Bigger is better, however you want to look at it my preference lies in the cheaper to make FET drivers. (I can build this for around $5, and I have built hundreds of them for the ~600 lights I have modded as well as for several other folks here.) I have a prototype boost driver or two, and have been told their price level, this is not something I would want to use in quantity, obviously a 5x greater cost would get ineffective very quickly. I don’t mind using them sometimes, but I do find it worrisome the resulting low discharge level if I forget the time it’s run and take the light to the cut-off point. I normally charge my cells when they still have a comparatively high charge, seldom taking a cell down to 3.7V… much less 2.5V! (or even less, as some regulated drivers will do)

I like what I like, I have no need to sell anyone on my preferences or ideas… I use my lights for my own purposes and as I have found over the past 6 years or so, a large part of my purpose is to tweak a light for all it’s worth. I have reason to mod lights for nothing more than the time it kills, the effort it requires, or the final number it can produce… so whether I use the modified light or not isn’t where the relevance lies in the end. This is most likely not how the larger public views things. It is, however, a large part of why I mod. Like asking a mountain climber why they climb mountains and they say “Because I can!”. In great part, for me, it’s like that with flashlights. :wink: (What, did you think I really NEED 230 flashlights?)

And yes, if/when I get a D18 I will mod it. I find I don’t really prefer the SST-20 so probably moments after I receive the D18 it will get new emitters… at the very least. :smiley:

I may even machine a spacer to fit the top end and make it a quad 3V 50.2, under a multi-reflector. This should maintain lumens output and actually keep it sustainable. We'll see...

FET or boost driver. Whatever Hank produces is just executed brilliantly, and it comes down to personal preference. :sunglasses:

If your asking if it has a built in circuit to prevent the batteries from being overly discharged then yes, it has this. It’s also called LVP or Low Voltage Protection.

Yes, thanks. LVP has the same meaing, yes.

@DB Custom,

Thanks for your response. I can totally relate to some of the points you brought up and like you said, totally up to personal preference. I never considered how low battery level and pulling full power can be bad for batteries. Glad I learned something new.

There will be those that will argue it’s not harmful to the cells, although I disagree. To each his/her own, I paid for all mine so I get to say how they are cared for or abused. :wink:

Let it be said that with 230+ lights on hand, and cells in every one with a good collection of reserve cells on standby… I have over 300 cells of various sizes and branding. Seriously. And I have only recently started having cells die off on me, old cells that have been used pretty harshly. I’m taking the safe route, usually. . . . :wink:

~342g without the batteries.

I was kind of hoping we could get TK to weigh it at the grocery store:

I’m really not sure what you mean by this.

The closest thing I can think of is the way that certain Boost drivers work. They can draw a certain number of amps on Turbo with a fully charged battery and as the battery voltage drops, the current will start to go up, but only up to a certain point. If the battery voltage drops too much and requires too much current it will simply not activate that Turbo mode. Instead it’s highest mode will be less than Turbo so as to keep the battery amp draw at a reasonable level.

Or maybe you mean like a Boost driver on Low mode that draws something like 1 amp continuously all the way down to the point it activates its low voltage protection?

I know a little bit about how Boost, Buck and FET drivers work, but maybe your talking about some other design?

Thank you TK for you detailed and informative review!

Double thank you for creating an amazing tint-mixing design that looks incredible!

I’ve just created a thread because I talked to Hank and he’s confirmed that he’s willing to build custom tint-mixed versions of the D18 for anyone for an additional $15!!

CUSTOM Emisar D18 builds are AVAILABLE!

Here’s one:

FWIW, I updated comment #2 with info about tint mixing. Before now, it just said “reserved”.

During my voltage testing, the M43 usually decreased in brightness when I turned down the voltage. However, a couple times, it didn’t. I don’t know what changed, but once in a while it would maintain approximately the same brightness regardless of voltage.

So I’m not sure what happened, but I have a guess. It looks like the current regulation might be controlled directly by the MCU, and it looks like the firmware might have a bug in its current regulation code. Most of the time it didn’t appear to work correctly, but once in a while, it worked fine. The behavior was very strange and unpredictable.

I tested at other levels too, not just 120 lm. I saw similar voltage-related sag at all levels… except once in a while when it didn’t happen.

As for the D18, I tested some other levels on FET+N+1 drivers too. As expected, the FET levels sag with voltage. The +1 levels are almost completely stable. But I saw something weird in the N+1 levels — they sagged too. And I’m not sure why. Maybe my PSU was having difficulty, or maybe there’s actually something not working right in the driver. At some point, I’ll have to do some battery-powered runtime graphs at like 3x7135 or so, to find out if it stays stable during actual use or if it sags.

What confuses me is that you tested a Nx7135 level on the ROT66, and found it almost completely flat. So it should work, but when I tried it, it didn’t. I guess I have a mystery to investigate.

The M43 has a typical Carclo 10507 beam pattern, which is basically a big wide hotspot with almost no spill. There’s a faint glow around the hotspot, but it’s very dim. Almost all the light is in the hotspot, and it’s pretty wide so I describe it as a wall of light. During use, I find that the hotspot is so wide that the edges of the hotspot light up nearby objects and this near-field illumination can make it difficult to see things in the distance.

The D4S beam looks more like a traditional reflector. It has a small and bright hotspot, and around it is a much dimmer but still usable spill area. The brightness looks like a flat round plate with a can of soup stacked on top, right in the middle. It’s basically two levels, like a - shape.

The D18’s beam looks similar to the D4S, except it also has a corona around the hotspot. So more of the light falls in the spill area, which gives it a lower cd/lm value. The brightness looks like that same “plate with a soup can in the middle”, except the soup can is surrounded by a hill of mashed potatoes. I guess it’s more of a .-. shape. Or, another way to picture it is an upside-down cup on top of a small hill. Or, now that I think about it, it’s shaped like a boob in cold weather. The D18’s brightness chart looks like a boob.

Perhaps I can get a beam shot with all three, but the tints are all different so it’ll look weird. They also each have pretty large beams so I’ll have to put them fairly close to a wall in order to fit them all in one frame.

For now, I’ll just make a diagram to describe approximately how the light is distributed within the beams:

ish

Yes. The D4’s moon mode was relatively bright, because of the firmware used. The D4S’s moon mode was relatively bright because it had three 7135 chips on that channel instead of just one. The emitters used probably also play into things here, and some variation between individual lights. But I’ve found the D18’s moon mode is lower than either the D4 or D4S.

I love me some large and full hotspots, with smooth transitions to minimal spill. It’s all the light where I want it, very little where I don’t want it.

D18’s beam profile doesn’t sound too tempting.

Thank you TK for the additional picture I asked for and for your thoughts between M43 and D18. :+1:

Yeah, it really depends on what you’re doing.

If you’re looking at a wide area which is all roughly the same distance away, the M43 works really well. For example, standing at the edge of a forest, looking at the tree line. Or looking at the nearest side of a building. It’ll provide a very evenly-illuminated view of something like that.

If you’re walking down a sidewalk or a road and want to illuminate the entire path going forward, the D18 beam works well. It gets more intense as it gets closer to the center, so if it’s aimed into the distance it illuminates the path to roughly the same brightness regardless of distance. This is my favorite beam type, overall.

If you want to look only at something in the distance, the D4S beam is a bit better. It won’t illuminate the near field as much. But it’s not what I’d call a thrower. It’s just toward the throwy end of EDC-style beams. It can still be used to illuminate a path going forward, but the hotspot has a sharp enough edge that the brightness of the path varies.

For really seeing something in the distance, none of these are throwy enough. I’d suggest a D1 or D1S for that.

Out of the D4S & D18, is the D18 closer to the Convoy L6 in terms of beam pattern?