Emisar D4 (V2)

This is the updated 2019 version of the Emisar D4, produced by Hank Wang of Intl-Outdoor.

Disclaimer: I helped make this. I’m not an impartial reviewer. This thread is primarily intended to answer everyone’s questions about this brand new product.

I reviewed the original Emisar D4 too, if you’d like more pictures, information, and background context about this light.

What’s New?

If you’re already familiar with the original D4 and just want to know what changed, here’s a quick run-down.

Compared to the original D4 with RampingIOS, the new D4V2 is updated in these ways…

Added an optional steel bezel

Added an optional tailcap magnet

Added a tailcap lanyard attachment point

More grip on the battery tube

Different host colors available

More LED types and tints available

types and tints available MCPCB is screwed down now

is screwed down now Larger MCPCB with dedicated screws holes, so the 4 optic legs are in intact in the D4V2

with dedicated screws holes, so the 4 optic legs are in intact in the D4V2 Rotated the LED s for a smoother beam

s for a smoother beam Added aux LED s with 7 configurable colors plus rainbow and voltage modes

s with 7 configurable colors plus rainbow and voltage modes Upgraded the driver to use a new MCU with more pins and twice as much space

with more pins and twice as much space Added spring-side firmware flashing pads to the driver, for easier updates

Fixed reverse polarity protection

Completely new firmware — Anduril instead of RampingIOS… so it has a lot more modes and options. More details on this below, since it’s too much to cover in this quick summary.

So it’s more or less the same D4 people have loved for the last two years… only better.

Official Specs

Battery type: Unprotected, high drain batteries only, protected cells won’t work

Aux LEDs: Red, yellow, green, cyan, blue,magenta, rainbow aux LED options is selectable through config UI, as well as the voltage indication function.

Features:

CNC machined from aircraft-grade aluminium

machined from aircraft-grade aluminium Efficient UK made Carclo Quad LED optics

optics Anti-reflective coated glass lens

Unihead construction

High lumen output and low moon output

Ramping interface

Electronic soft touch switch

Beryllium-Copper springs with 45% IACS superior to stainless steel alloys used for springs with only 2% IACS .

superior to stainless steel alloys used for springs with only 2% . Temperature step-down

Waterproof and dustproof to IP67 standard (up to 1 meter)

Default 18650 body with optional 18500 or 18350 battery tube

Dimensions: 95mm(length) * 28mm(head) * 24mm(body), 80mm(lenght 18500), 63.5mm(lenght 18350)

OTF lumen output at start-up

XP-G2 S4 : 3300lm

Nichia 219C : 3000lm

XP-L HI : 4300lm

SST -20 6500K : 4200lm

-20 6500K : 4200lm SST -20 5000K : 4200lm

-20 5000K : 4200lm SST -20 4000K/3000K 95CRI : 3000lm

Measurements

Output:

Beam type: Hotspot plus corona, narrow spot or floody depending on the optic chosen

Power: As much as your battery can push (probably around ~15 A)

LED s: Cree XP-L HI, Nichia 219C, or Luminus SST -20

s: Cree XP-L HI, Nichia 219C, or Luminus -20 Brightness ~0.2 lm at bottom of ramp, ~2500 lm to ~4500 lm at top of ramp depending on LED type and battery, plus a smooth ramp between

Dimensions:

Length: 95.2 mm

Bezel diameter: 28.0 mm

Head diameter: 30.2 mm diagonal

Body diameter: 24.0 mm

Clip groove diameter: 22.6 mm

Lens: 25.6 × 1.5 mm

Driver: 21.9 mm diameter, 1.7 mm thick PCB , 3.3 mm w/ components

, 3.3 mm w/ components Maximum cell length: 67 mm (protected cells won’t fit)

Host / Build:

Weight: 73.9 g w/ steel bezel and magnet tailcap, 119.6 g w/ battery

Switch type: Momentary / electronic side switch

Body material: Hard anodized aluminum: black, grey, or sand (maybe other colors later too)

Lens: Glass

Anti-roll and tail-stands nicely

Waterproof to IP67 (1m underwater) (from specs, not measured)

Premium BeCu (Beryllium Copper) springs capable of high current without sagging

Optic: Carclo 10622 / 10623

Electrical:

Driver type: FET +1 (regulated up to 350mA or ~140 lm, hybrid direct drive at higher power levels)

+1 (regulated up to 350mA or ~140 lm, hybrid direct drive at higher power levels) Operating voltage: 2.8V to 4.35V

Battery: One 18650, 18500, or 18350 cell (with matching tube)

Parasitic drain: ~0.02 mA with aux LED s off (17 years to drain a 3000mAh cell) ~0.06 to ~0.12 mA with aux LED s on low mode (2.5 to 6 years) TBD mA with aux LED s on high mode (my sample has different resistors, so I can’t measure) (probably about ~0.2 to ~0.4 mA on blinky mode, or 1 to 2 years runtime) (probably about ~3 mA on high mode, or about 50 days runtime)

Low-voltage protection: Yes

Thermal protection: Yes

Reverse polarity protection: Yes

Power can be locked out by loosening the tailcap, or by entering a lock-out code on the button

MSRP: $45 USD

Interface

TL;DR: Click for on/off, hold to change brightness. That’s all you really need to know to use this UI.

Beyond that, the user interface (UI) has … a lot of features / functions. There’s a good chance that, if you want a specific thing, there’s probably a way to do it. I’d suggest reading the manual for general info about how it works, or referring to the UI diagram below. Or both.

If it helps, here’s a partial list of what changed in the UI between the original D4 and D4V2:

Instead of just smooth ramping, there is also a stepped ramp with discrete levels… and switching between the two is quick and easy

Both ramps have configurable floor and ceiling levels, and the user can choose how many steps in the stepped ramp

Made ramp direction predictable, and added a shortcut to ramp down

Added an option to choose between automatic or manual memory to choose the brightness at single-click from off (automatic uses the last-ramped level, manual uses a level the user explicitly configured)

Made moon mode lower, and dramatically increased moon mode runtime

increased moon mode runtime Added more modes behind the battery check mode: Sunset, Beacon, and Temperature Check

Moved Lockout mode from 6 clicks to 4 clicks for faster access

Made Lockout mode double as a momentary moon mode with 2 levels of output, so it doesn’t need to be unlocked for quick tasks

Made confirmation blinks much faster

Added a “Muggle Mode” on 6 clicks, to make the light safe when lending it to other people (is limited to only safe levels, and all other modes are inaccessible)

Moved Beacon mode into the battcheck mode group, and made its blink shorter

Made Beacon Mode’s timing and brightness configurable

Much smoother thermal regulation

Changed thermal config from “hold until hot” to a sensor calibration step plus an explicit temperature the user can enter precisely

Added support for colorful aux LED s

s Added an entire group of strobe / ambient modes: adjustable Party Strobe, adjustable Tactical Strobe, adjustable Bike Flasher, Lightning Storm mode, and adjustable Candle Mode with configurable self-shutoff timer

Made Momentary Mode brightness configurable

Made Momentary Mode work with strobe-group modes too, for momentary strobes (good for light painting)

The new firmware is a complete from-scratch rewrite, but the basic usage is the same: Click for on/off, hold to change brightness. That’s all you really need to know to use it.

Aux LED s

The aux LEDs turn on during the “off” and “lockout” modes. They are off in other modes, like when the main LEDs are on.

This animation shows frames from a video while the light is in “rainbow” mode:

The rainbow mode looks exactly like this animation; it doesn’t fade between colors because that would require keeping the MCU awake, and that would greatly reduce the standby time.

The aux LEDs have four brightness levels (modes) and nine colors.

Brightness levels / modes:

Off

Low

High

Blinking (1 Hz low/high pattern)

Colors:

Red

Yellow

Green

Cyan

Blue

Purple

White (ish)

Rainbow animation

Voltage (blue = good charge, green = medium charge, red = low battery, off = critical battery)

These can be configured independently for the “off” mode and the “lockout” mode, so the user can tell at a glance whether the light is locked or just off.

To change the aux LED brightness level / mode:

In “off” mode: Click 7 times.

In “lockout” mode: Click 3 times.

To change the aux LED color:

In “off” mode: Click 7 times, and hold the last click until the desired color is reached.

In “lockout” mode: Click 3 times, and hold the last click until the desired color is reached.

The modes and colors are in the order shown above. Rainbow mode is indicated by cycling colors, while voltage mode is indicated by faster cycling colors.

Here’s how the MCPCB and aux LED board look. My sample has different resistors than the production version, but it should otherwise be the same.





I tried to measure aux LED power use. I can’t say for sure my numbers are good, since my D4v2 has the resistors set up differently than a production model, and my measuring equipment isn’t very precise at low power levels, but here’s what I got…

Low mode (rainbow): 0.077 mA to 0.107 mA, depending on how I measure

Runtime: 3.7 to 5.2 years

High mode (rainbow): 2.89 to 3.01 mA, depending on how I measure

Runtime: 48 to 50 days

Blinky mode (rainbow): 0.205 to 0.424 mA, depending on how I measure

Runtime: 0.9 to 1.9 years

For comparison, here’s moon mode, the bottom of the ramp:

Moon mode: ~1.8 mA

Runtime: ~81 days

These were each sampled over time and then averaged. The power source was set at 3.7V. Runtimes assume a 3500 mAh cell.

Packaging

The light comes in the same packaging as other Emisar lights, which is simple but very effective at keeping the light safe during shipping. It’s a cardboard box which is heavily padded inside. It could probably fall off a plane and not cause any harm to the light inside.

I … kinda forgot to take pictures of the packaging, but it looks identical to the original D4 packaging except it says D4V2 on it. Here’s how that looked in 2017:

Comparison to other lights

Emisar D4 (original) vs Emisar D4V2:



Emisar D18 vs Emisar D4v2:



Host, Components, and Build Quality

The D4V2 has an O-ring and square-cut threads on both ends. The battery tube has a square knurling pattern for grip, and recessed grooves for attaching a clip. The tailcap has grip ridges and a lanyard attachment point.





The button still sticks out like the original D4, which makes it easy to press.

The lanyard hole’s edges are chamfered to make sure it won’t cut through the lanyard string:

The driver has pads for flashing firmware, which makes it really easy to update… if you have a pogo pin adapter. Without the adapter though, it’s nigh-impossible because the attiny1634 MCU doesn’t fit a SOIC8 clip.

I would not recommend trying to remove the driver. It’s glued like the original D4, but more importantly, it has a lot of wires! Here’s how the top side looks in my early prototype, with its brain hanging out:

Tailcap Magnet

There’s a magnet in the tailcap, if you want one. It sticks to stuff. For example, a door clasp:

… or a coated wire shelf:



… or even a single screw hanging from a vibrating ceiling fan:



The magnet is not as strong as the D4S magnet. It’s not quite as “friendly”, so to speak. But it’ll still stick to pretty much anything solid and ferrous.

Beamshots, Output, and Runtime

… eventually!

(sorry, trying to post this review quickly to answer people’s questions… and the questions aren’t about the beam… because people mostly already know what the beam and runtime are like)

Default configuration:

Ramp segments: Level 1 to 65: AMC7135 chip only Level 66 to 149: AMC7135 + FET Level 150: FET only

Smooth ramp: 1 to 120

Stepped ramp: 10 to 120 in 7 steps: 10, 28, 46, 65, 83, 101, 120

Thermal regulation

Compared to the original D4, the thermal regulation is much smoother. It’s mostly not noticeable when it makes an adjustment during use. It’s also far less prone to jumping around, so when it finds an optimal level it pretty much just stays there. Here’s how it looked during the first 10 minutes in a recent test:

The numbers on this graph are very approximate. I don’t know what the actual peak output was; just the relative brightness throughout the test. I scaled the graph according to the official specs, minus an arbitrary correction factor since my battery is getting a bit old so it’s not as bright as it would be with a fresh cell.

Source Code

… will be released soon. I’ve been a bit busy.

This light runs Anduril, and is thus supported by the FSM UI toolkit. That means it’s pretty easy to run other interfaces if desired. If you can describe your desired interface in the form of a flowchart, you can probably make it run on the D4V2.

Potential Issues

First off… THIS LIGHT CAN START FIRES. You have been warned. Be careful. Lock the light while carrying it.

The second potential issue also relates to heat. Thermal regulation is difficult on such a hot light, so it may exceed the configured temperature limit for a little while when turbo is activated. Over time it settles back to a comfortable temperature, but in turbo mode it can get very hot in just a few seconds.

With the aux LEDs on high mode, I don’t know how much power is used on the production version. I couldn’t measure that, since my sample has different resistors and thus different aux LED power use.

The clip is a clip-on type, not a screw-on or ring-in type. So it may scratch the anodizing around the clip attachment point.

Upgrade / Mod Options

The most obvious ways to modify this light are:

Change the optic. It uses a standard type, so you can swap in other compatible optics.

Change the emitters / MCPCB . Intl-Outdoor and MtnElectronics both sell compatible parts, though only the Intl-Outdoor boards will screw down.

. Intl-Outdoor and MtnElectronics both sell compatible parts, though only the Intl-Outdoor boards will screw down. Glow tape or tritium vials could be added, but it may be redundant due to the aux LED s.

s. Firmware changes. This is easy to do if you have a pogo pin adapter, but difficult otherwise.

Most of the changes people would be likely to make are available as options while ordering. For example, a clip, a tailcap magnet, different emitter types, and different optics.

Summary

What I liked:

… phew. Almost everything, really. This light sets the standard for what a pocket rocket can be.

The steel bezel is a nice upgrade.

The clip is much better than the original D4 (which had none, and then had a kinda bad one, and then finally got a decent clip) (D4V2 uses the finally-decent version).

Basically all the upgrades are very welcome improvements to the tried-and-true D4.

I particularly like the firmware flashing pads, but I may be part of a pretty small population who cares about that.

Many choices of emitter type and tint, to suit almost anyone’s taste.

It ships with a full-featured version of the latest Anduril.

Emisar laid new foundations for the next generation of flashlights, and that makes things better for all of us — even those who don’t actually buy the D4V2. When new tech shows up in other lights, it’s likely because of the work Emisar did.

Things I feel neutral about:

Side switch still sticks out.

The knurling feels a bit aggressive.

Higher regulated modes would have been nice, but it’s not really a big deal.

What I didn’t like:

I’m not a big fan of the sand/gold/tan color.

On turbo, it gets hot very fast!

The End

Or an end, anyway.