Emisar D4SV2 Review – Three Versions Compared!


The Boring Stuff

I purchased the dual-channel variant with my own money from intl-outdoor.com. Here is the official product page for that. The standard and boost variants were kindly lent to me for testing by reddit user u/mobiuscorpus. Many thanks! Here is the official product page for those. At the time of writing, D4SV2 starts at $58 for the base model and goes up to $93 depending on your configuration. Note: the extended 26800 body tube must be purchased separately for $14.

What comes in the box?

The box is a simple cardboard box that opens via a top flap. There’s a sticker on top noting the contents and a nice foam insert inside to protect the contents. The following items are included in the box:

  • The light itself (with aluminum bezel installed)
  • Spare o-rings
  • Lanyard
  • Stainless bezel (if purchased)
  • Additional floody optic (if purchased)
  • Spare tailcap (if purchased)

Design & Construction

D4SV2 is a scaled-up version of Emisar’s popular EDC model: D4V2. The biggest changes are a larger diameter (to fit a larger battery & deeper optics) and a recessed switch.

Build quality is excellent, as is typical of Emisar/Noctigon flashlights. The threads are long, trapezoid cut, anodized, and lubricated. The ones on the grey and cyan models are exceptionally smooth as well. They’re identical on both ends, so the body tube can be reversed if you ever need to for some reason.

Size & Measurements

From left to right:
Thrunite TC20 V2
Emisar D4SV2 (default 26650 body)
Emisar D4SV2 (extended 26800 body)
Emisar D4SV2 (extended 26800 body)
Noctigon KR1

MeasurementMeasured (mm)
Bezel Diameter39
Maximum Head Diameter42.3
Length (with 26800 tube)120.6
Switch Diameter11
Switch Proudness-1
Lens Diameter36.0
Lens Thickness2.0
Optic Diameter34.1
Optic Height (at MCPCB)10.7
MCPCB Size33
26800 Body Tube Diameter (internal) 27.0
26800 Body Tube Diameter (maximum)34.0
26800 Body Tube Diameter (mode)32.4
26800 Body Tube Length85.8
Pocket Cip Slot Width3.0
Pocket Clip Slot Diameter31.0
Tailcap Diameter35.0
Tailcap Length17.9
Driver Diameter30

Weight with 26800 battery installed: 278g

User Interface

This is an enthusiast light, so it’s fitting that it has the best enthusiast UI: Anduril 2. It’s a highly-configurable and feature-rich UI that’s not for the faint of heart, but it’s a joy to use if you know it well. I’m not remotely prepared to do a whole UI breakdown, so I’ll just direct you to the official Anduril 2 Manual which has a UI table at the bottom. With that said, here are a few of my favorite features. Most of these are highly configurable or optional, so if you don’t like one, you can probably disable or change it!

  • Momentary Turbo
  • Adjustable Thermal Ceiling
  • Adjustable Stepped Modes
  • Manual Mode Memory
  • Shortcuts to & from Moonlight, Turbo, and high.
  • Battery voltage readout

Note: If you order the standard single-channel version with no special requests, it may come with Anduril 1 installed.

Modes, Brightness, Throw, & Tint

Disclaimer: Lumen measurements were taken on a Texas Ace 3.5″ Lumen Tube. A candela measurement was taken at 10 meters with an Opple Light Master III on the highest brightness, and other candela figures were calculated relative to that. CCT & DUV data was taken for each mode from a few feet away at the center of the hotspot with the Opple Light Master and Waveform DUV Calculator. Runtime tests were performed with the Ceilingbounce app on my smartphone. All of these tests were performed with a fully charged Queen Battery QB26800 battery unless otherwise specified. I cannot measure moonlight directly, so moonlight readings are calculated based on the brightness relative to the next-lowest mode. None of this is professional equipment, so take all of these measurements with a grain of salt.

Level Lumens (@ Turn-On)Candela (@ Turn-On)Throw (meters)CCTDUV
2-Channel Driver | LH351D Flood Channel
Level Lumens (@ Turn-On)Candela (@ Turn-On)Throw (meters)CCTDUV
2-Channel Driver | W1 Throw Channel
Level Lumens (@ Turn-On)Candela (@ Turn-On)Throw (meters)CCTDUV
Stock Linear+FET Driver | Osram W2’s
Level Lumens (@ Turn-On)Candela (@ Turn-On)Throw (meters)CCTDUV
Boost Driver | Osram W2’s

Tint: Both variants with W2’s ended up having significantly positive DUV. I’m leaving the numbers in here so that you can see them, but I don’t think the DUV numbers for the W2 variants reflect the actual tint of the light. To my eye, the Linear+FET driven version looks a little bit rosy and the Boost driven version looks neutral to slightly green, but not that green. The DUV measurements for the dual channel version do accurately reflect what I see.

Why those modes? Anduril 2 has 150 levels, so doing measurements and tests for each mode is virtually impossible. I’ve got these light set up how I like it with 5 levels. Bottom of ramp is level 1, top of ramp is level 120 for single channel lights or level 130 for dual channel lights. I’ve set up the stepped ramp with 4 steps so, with turbo added, I get the 5 modes I like. Because I use manual mode memory on the middle mode, that gives me shortcuts from off to Moon, Medium, High, and Turbo.

Mode Spacing / Ramp Speed: Mode spacing is good. There are no jumps that feel too large or too small when using the stepped ramp. The smooth ramp is an appropriate speed throughout. That’s unusual because most smooth ramping lights ramp too fast at the low end and too slow at the high end.

How does it compare to the official specs? There are no official specs for these configurations.


These tests were all performed after thermal calibration, and the two W2 variants were both calibrated at the exact same time to minimize any calibration differences.

2-Channel Variant Runtimes: LH351D | W1

Performance (2-channel): Turbo and High modes heat up and step down fast, as is expected. Sustained output is in the 400-500lm range. This is with the stock thermal limit of 45C and after thermal calibration was performed, but the light felt cooler to the touch than I expected so it’s possible my thermal calibration was a little off. You could easily get better sustained output by raising the thermal ceiling, or even just by holding the light while its in use.

Performance (Standard VS Boost Drivers): The boost driver takes a lot longer to heat up and step down (even at the same brightness level, see Linear+FET high vs boost Turbo in the thermal stepdown graphs). The boost driver maintains ~40% higher output too, which is nice.

Efficiency: In this last graph, I got the Linear+FET driver and the Boost driver variants (both with the exact same LED’s and batteries) down to levels that are easily thermally sustainable and as close together as I could. Then I did a runtime test to see which one was more efficient. The boost driver won, and by a lot bigger margin than I expected. Set to the exact same brightness, I would expect the boost driver to last 20-25% longer than the Linear+FET driver. There was no discernable heat difference between the two in this particular test, but you can see in the other graphs that the boost driver clearly generates less heat because it maintains a higher brightness.

LVP: Is present and works great. Anduril has the best LVP implimentation I’ve seen. When the cell reaches 3 volts (approximately), the light will dramatically reduce its brightness to serve as a low voltage warning and to extend battery life, then will shut off when the cell reaches 2.7v. In the case of Linear or FET driven lights, this provides several hours of use on moonlight mode between low voltage stepdowns and low voltage shutoff. On the boost driver though, there’s very little runtime between stepdowns and shutoff. The lights can be re-activated after shutoff for a few minutes of emergency power, but in the case of the boost driver, the LED’s don’t actually come on when the cell is near empty. The light acts like it’s on, but no light comes out.

Driver & Regulation

Linear+FET | Boost
Linear+FET | Boost

There are several drivers available for D4SV2. For a long time, it had a FET+3+1 driver based on 7135 chips for regulation. That’s the standard driver option if you don’t elect for anything special and it works just fine. I think this driver comes with Anduril 1, and it’s the only driver option that doesn’t support a lighted switch.

There’s also a 9A Linear+FET driver available by special request. If you ask for it specifically, or if you ask for a lighted button without specifying a driver, you’ll get the Linear+FET driver. Interestingly, it comes with K9.3’s firmware installed on it for some reason and Hank confirmed that’s normal. That means that 3H for momentary turbo doesn’t work. It switches to the other, non-existant channel. This is the driver I have in the Cyan sample.

There’s also a boost driver option for the single channel version, it should provide longer runtime, higher sustained output, and better regulation, but it can’t get as bright or as dim. This driver uses the DM11 Boost firmware. This is the driver I have in the Grey sample.

Finally, there’s a dual-channel driver which has its own separate product page. It’s two linear channels put together so you can smoothly ramp between or instantly switch between two different sets of LED’s. This is the driver I have in the black sample. I didn’t include photos of the dual-channel driver because it looks identical to the Linear+FET from the visible site except that it just has the one blue dot, no red dot.

Dual Channel Driver: LH351D Flood Channel | W1 Throw Channel

Regulation (2-Channel): Regulation looks typical of Hank’s Linear drivers. Lower modes are well regulated, higher modes dim with battery voltage.

Regulation (Linear+FET vs Boost): The Linear+FET driver has average regulation. Higher modes are affected by cell voltage but lower ones aren’t. The Boost driver is very well regulated, except the emitters would not turn on at all when the cell was at 3V. It acted like it was on. the aux LED’s would turn off and the switch LED would change as I “adjusted the brightness”, but absolutely no light came from the W2’s. I have no explanation for this. Despite the Boost driver’s great regulation, the Linear+FET driver can still achieve a higher brightness than the Boost driver at almost any voltage level and on almost any mode.

Note: All regulation measurements are taken at turn-on so they do not reflect any thermal or low voltage stepdowns that may occur. A value of 0 indicates low voltage shutoff immediately upon activation (or in the case of the boost driver variant, a failure for the LED’s to actually turn on at all).

Thermal regulation: Is present and works very well. Anduril has the best thermal regulation I’m aware of. Best of all, you can customize the thermal limit on your light. If you’re just ceilingbouncing or always wearing gloves, you can increase the thermal limit to 70C for higher sustained output. If you want to make sure the light never gets too warm, you can leave it at the stock 45C or even lower it down a bit.

PWM (Linear+FET Driver): No PWM is visible to my eye. I did some testing on each mode with an Opple Light Master III and found some flickering (but not PWM) on the lowest mode. All the other modes I used were flicker free. I also arbitrarily stopped at a level between High (level 120, max regulated) and Turbo (level 150) and that had PWM because it’s outside the constant current regulated part of the driver, but not quite full direct drive.

PWM (Boost Driver): No PWM is visible to my eye. I did some testing on each mode with an Opple Light Master III and found some flickering (but not PWM) on the lowest mode and some sawtooth on Low (level 40). The other modes were flicker-free.

Parasitic Drain: With aux LED’s disabled, the Linear+FET driver measured in at 30 microamps. I could not get a reliable reading from the boost driver because it would not power up when connected through my DMM. I did not measure parasitic drain for the dual-channel driver.

Emitter & Beam

Dual Channel (LH351D & W1) | Single Channel (W2)

Notably, the Black & Cyan hosts are un-anodized inside the head, while the Grey host is anodized. The grey host’s aux LED’s appear dimmer as a result. You might also notice that the LED’s are all rotated a little bit differently than all the others. That is done deliberately to try and minimize beam artifacts. Very clever!

Dual Channel (LH351D & W1) | Single Channel (W2)

D4SV2 is available with a huge variety of emitters. Check the website to see what’s currently available. I’ve got three to test. The Black Dual-Channel host has Samsung LH351D 5700K’s and Osram W1’s. The Grey and Cyan hosts have Osram W2’s.

Dual Channel Driver: LH351D Flood Channel | W1 Throw Channel
Linear+FET (Turbo) | Boost (Turbo)

The W1 beam is narrowest. There are some artifacts on the edges of the spill, but you get W1’s for the throw, not for the pretty beam. W2’s are similar, but there are four of them instead of two so there are fewer artifacts. They produce a slightly wider hotspot than W1’s.

LH351D’s are significantly wider than the others and produce a nice, artifact-free beam. I would install some DC-Fix over them if you’re going for a flood/throw combo because with these deep D4SV2 optics they still aren’t quite as floody as I want.

LH351D Flood Channel | W1 Throw Channel
W2 FET Driver | W2 Boost Driver

In the beamshots above, the trees where I’m aiming the hotspot are 175M away. In the beamshots below, the park bench where I’m aiming the hotspot is 42M away.

LH351D Flood Channel | W1 Throw Channel
W2 FET Driver | W2 Boost Driver

Aux LED’s: The main white LED’s aren’t the only LED’s in D4SV2. It also includes sixteen RGB auxiliary LED’s behind the optic, and can have single-color LED’s installed behind the switch too. If you don’t see a backlit switch option on the product page, just email contact@intl-outdoor.com with your order number and request a backlit switch and your backlight color preference and he will install it for free.


D4SV2 uses an electronic side switch. The dual-channel version is backlit by default. The single channel is not, but you can request a backlit switch in your color choice via email after placing your order and Hank will install it for free. The switch lights are not RGB, so you’re stuck with the color you choose. It’s a good switch. It’s clicky, but not super tactile. It’s recessed so it’s highly unlikely to activate by accident. It’s in a good spot so it’s easy to reach. I like it.

Carry & Ergonomics

Ergonomics with the 26800 tube are excellent. The body tube is the right diameter and texture for a good grip. The button is in just the right spot to be easy to use as well. It’s almost as nice with the 26650 tube, but I can’t get a full grip on it and it is a little clumsy at times. The whole light just feels dense and well-made in hand. Hank did an impeccable job here.

There’s a lanyard included in the box for carry. It’s fine. I don’t do lanyards.

I wanted a pocket clip on my D4SV2, so I modified a KR4 clip for that purpose. I cut the clip ring directly across from the clip and slowly bent the ring out to make it large enough to fit around D4SV2’s tail threads. Then I placed some 24AWG copper wire in the tailcap to act as a conductive spacer, so the light would work. When I crank the tailcap down, it holds the clip in place quite securely. It carries deep, goes in and out of the pocket easily, and doesn’t prevent tailstanding.

D4SV2 also (optionally) features the strongest magnetic tailcap I have ever used. It has no trouble holding this big light up on a vertical surface even with a heavy 26800 battery installed.

Batteries & Charging

D4SV2 takes a single, unprotected, flat top, 26mm diameter cell. For best performance (especially with these W2’s) you really want a cell that’s rated for 20A (or more) continuous drain. By default a 26650 tube is included, but you can buy an optional (and highly recommended) 26800 tube for a few more dollars. I did all my testing with Queen Battery QB26800’s. It’s a big improvement and I think it fits the light better than a 26650. It makes it feel more like a scaled-up D4V2 ratter than just a fatter D4V2.

No charging solution is included. You shouldn’t have any trouble finding a 26650 charger, but 26800’s are very long and don’t have a lot of options. Nitecore’s UI2 is the charger I’m using at the time of writing, but Xtar will release their SC1 Plus charger soon which will likely be a better choice.

There are over hundreds of different possible configurations for D4SV2. Here are three configurations that I think make the most sense:

Output & Throw Monster: Osram W2 LED’s with a Linear+FET driver. Nearly 5000lm & 100kcd. This is the config I’m testing in the Cyan body color, and is the one with the most wow factor.

Runtime King: SST20 5000/6500K LED’s with the Boost driver upgrade. Will have very high efficiency, great sustained output, and long runtime. Great for extended use as a tool rather than a toy. Note: get dedomed Nichia 519A’s instead if you need pretty tint & high CRI, but they won’t be as bright or efficient.

Flood/Throw Switcher: Dual channel driver with Osram W1’s for throw and domed Nichia 519A’s for flood. I tested this configuration with LH351D’s on the flood channel, but Hank now stocks Nichia 519A’s and I think those are a better choice. I also recommend putting some DC-Fix over the flood lenses just for a little bit wider beam.


Here are some lights in the same class and how they compare.

Astrolux MF01 Mini: 21700 or 26650 battery, unicorn barf colored aux LED’s instead of RGB, USB-C charging built in, far fewer LED options, 7 LED’s instead of 4

Emisar D4V2: Basically the same as D4SV2 but smaller (edc size), uses an 18650 battery, and has a floodier beam. Reviewed here.

Fireflies E07 2021: smaller, lighter, has a pocket clip, 7 emitters instead of 4, single-color aux LED’s instead of RGB, 21700 battery instead of 26XX0. Reviewed here.

This section is not comprehensive. If I didn’t include a particular light here, it doesn’t mean it’s bad or doesn’t deserve to be here. I simply cannot list every possible competitor.


D4SV2 is a fabulous upgrade from D4V2 if you want the same features but with more power. There are so many options to choose from that you can get almost anything you want. This is one of the best enthusiast lights on the market and I highly recommend it.

Thanks again to u/mobiuscorpus for lending me the Cyan & Grey samples for testing!

4 thoughts on “Emisar D4SV2 Review – Three Versions Compared!

  1. Sorry for asking stupid question but your answer has been deleted from Reddit with your old account…
    What do you recommend in D4SV2 dual channel?
    W1 or W2? Why?….

      1. Oh… thanks!
        Hank added 519A emitter option today… so I probably will order 519A 4500K / W1 6000K D4SV2 for my first Hanklight ever. I hope I’d be happy with this choice 🙂

        BTW – nice review! Kudos for all of your effort here & on the reddit – GOOD JOB!

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