Noctigon K1

The K1 is Noctigon’s first long-range thrower flashlight, produced by Hank Wang of Intl-Outdoor. It can illuminate things ~1.55 km (almost a mile) away.





This isn’t really a review though. I helped make the K1, so I can’t give an unbiased review. Instead, this is more of a general overview of what the light is.

Hank is also known for making Emisar products, which use direct-drive power circuits for the absolute maximum output. But the K1, like the Noctigon M43 Meteor before it, uses a regulated driver.

Intl-Outdoor Lights So Far

To help place this light in context, here’s a quick overview of the flashlights made by Intl-Outdoor. It’s sorted by throwiness (cd/lm), from widest to narrowest beam:

Name cd/lm battery lumens throw Emisar D4 (v2) 3 – 5 18650, 18500, 18350 3000 – 4200 ~10 – ~20 kcd Emisar D18 4.5 3×18650 10,000 – 14,000 45 – 65 kcd Noctigon M43 4.5 – 6.0 4×18650 5800 – 8200 30 – 52 kcd Emisar D4S (v2) 6 – 14 26650, 26350 3000 – 5100 27 – 58 kcd Emisar D1 33 18650, 18500, 18350 1300 43 kcd Emisar D1S 100 18650 1300 130 kcd Noctigon K1 ~685 21700, 18650 ~850 550 – 650 kcd

The new K1 is the throwiest light… by a wide margin. It’s even more throwy than the BLF GT Giga-thrower, despite being a fraction of the GT’s size. (the GT makes about 500 cd/lm, compared to ~685 for my K1)

Official Specs

Features:

CNC machined from aircraft-grade aluminium

machined from aircraft-grade aluminium Smooth aluminum reflector

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% . Constant current, temperature step-down

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

Dimensions: 173mm(length) * 72mm(head) * 26.5mm(body)

OTF lumen output

W1 (Osram CSLNM1.TG): 900lm, Lux : 650Kcd(650,000cd)

W2 (Osram CSLPM1.TG): 1400lm, Lux: 550Kcd(550,000cd)

Battery type: Unprotected 21700 cell, unprotected 18650 cell with an adapter, or an extra-long protected 18650 cell with a sleeve.

Button lighting: Red, yellow, green, cyan, blue, magenta, rainbow button LED options are selectable through config UI, as well as the voltage indication function.

MSRP: $79.95 USD

Measurements

Output:

Beam type: Narrow spot + dim spill

Power: ~4 mA to ~4.9 A (estimated)

LED : Osram 1mm White Flat CSLNM1.TG

: Osram 1mm White Flat CSLNM1.TG Brightness ~2 lm to ~900 lm

Candelas: ~1.5 kcd to ~600 kcd

Throw: ~77 m to ~1550 m

Dimensions:

Length: 173 mm

Bezel diameter: 72.3 mm

Switch section diameter: 41.0 mm

Body tube diameter: 26.5 mm

Tailcap diameter: 28.0 – 28.5 mm

Driver: 30 mm diameter

MCPCB : 32 mm custom Noctigon specifically for K1

: 32 mm custom Noctigon specifically for K1 Maximum cell length: 71 mm (protected 21700 cells won’t fit)

Host / Build:

Weight: 316 g, 385 g w/ battery

Weight (tail only): 56.4 g

Switch type: Momentary / electronic side switch with RGB backlight

backlight Body material: Hard anodized aluminum: black, grey, or champagne

Lens: Glass w/ AR (anti-reflective) coating

Includes anti-roll texturing, and can tail-stand on flat surfaces if not disturbed

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

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

Electrical:

Driver type: regulated linear FET

Operating voltage: 2.8V to 4.35V

Battery: One 21700 or 18650 cell (with adapter) (recommended battery is a Samsung 50E 21700 cell)

Parasitic drain: ~0.02 mA with button LED s off (28 years to drain a 5000mAh cell) ~0.06 to ~0.12 mA with button LED s on low mode (4.7 to 9.5 years) ~2 mA with button LED s on high mode (~3.5 months) probably about ~0.2 to ~0.4 mA on blinky mode, or 1.5 to 3 years 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

Packaging / Unboxing

The K1 comes in a standard Intl-Outdoor box, 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.

Inside is the light, a holster, and some accessories: a lanyard, two O-rings, and a spare button cover.





Comparison to other lights

I only have one light I can really compare the K1 to. Nothing else measures up:

(left: BLF GT, right: Noctigon K1)



The K1 is sort of a cross between the Noctigon Meteor and the Emisar D1S, only with better performance than either one. Here’s the Noctigon Meteor M43, Noctigon K1, Emisar D1S, and Emisar D1:

… and the whole Intl-Outdoor family:

(M43, D4, D4S, K1, D1S, D1, D18)



Built-in Charger

The K1 is really two devices in one, and can be split apart. The front is a flashlight, and the back (or the handle) is a 21700 battery charger. Unscrew the handle to access the charger:





Threads are all square, lubed, and quite nicely machined. Apologies for the lint which found its way into the photo.

Plug it in with a USB-C cable, and it charges the cell inside. It cannot do this while the main LED is on though, because the handle must be physically unscrewed from the front half of the light to expose the USB port. This keeps it waterproof without any flimsy rubber flaps.

I connected the charger to a USB-A wall power adapter rated for 2A, and measured a charging rate of 1.7A at the USB port. After converting the voltage, this translates to 2.0A at the battery. So the K1’s charging rate seems to be 2A. This means it should be able to charge a 21700 cell in about 2 to 3 hours.

After finishing a charge, the indicator lights go from red to green. On mine, this happened at 4.16V. It’s probably the same precision as most chargers — 4.20V +/- 0.05V. And since I prefer my chargers to stop early, I’m happy with this result.

About USB-C compatibility, I have no idea whether it supports any standards which are specific to USB-C. I don’t have any chargers or cables which support that, so I haven’t tested it.

Host, Components, and Build Quality

The button should look familiar to anyone who has used a Meteor.





Ignore the scratches around the button… Hank left some parts loose for me for development purposes, and I don’t have a 5-point tension device to tighten the button retaining ring, so I used pliers and scratched it a bit.

The lanyard hole is chamfered all around, to make sure it won’t cut through the lanyard itself.

The driver has pads for flashing firmware, which makes it really easy to update if you have a reflashing kit. Apologies for over-exposing the picture to make the driver visible:

Here is how the programming adapter is used (on a different light):



I would not recommend trying to remove the driver. It’s glued, and it has a lot of delicate wires inside. Swapping the LED would be relatively easy, but I’d suggest leaving the driver itself alone to avoid breaking any of the wires or contact pads.

Output

In the default stepped ramp with an Osram 1mm White Flat LED, I measured output at the following levels at start:

Moon: 2 lm / 1480 cd (77 m)

1/7: 9 lm / 5930 cd (154 m)

2/7: 52 lm / 34.9 kcd (374 m)

3/7: 126 lm / 84.8 kcd (582 m)

4/7: 238 lm / 160 kcd (800 m)

5/7: 381 lm / 256 kcd (1012 m)

6/7: 550 lm / 369 kcd (1215 m)

7/7: 723 lm / 486 kcd (1394 m)

Turbo: 874 lm / 599 kcd (1547 m) (564 cd at 30 seconds)

I’m not sure the lumen numbers are correct, because my lumen tube favors throwy lights. So the real lumen numbers are probably a bit lower. However, the throw numbers are probably pretty close or even a bit lower than reality. My lux meter usually measures lower than other people’s, so the maximum throw might actually be above 600 kcd.

Also, yes, it really does throw 77 meters in moon mode. It’s easily enough for me to see things 30m away across the street.

Default configuration:

Smooth ramp: 1 to 130

Stepped ramp: 10 to 130 in 7 steps: 10, 30, 50, 70, 90, 110, 130

Button LED modes: Off: voltage (low) Lockout: rainbow (blinking)

modes:

Beam Shots

Here’s how the light looks while it’s on:

Since cameras don’t have as wide a dynamic range as an eye, here are three different exposure levels to better illustrate how the beam looks.

There’s a weird hole in the middle, so I wonder if mine is broken.

(and for some reason I suddenly want a donut)

What’s that, you say? I’m doing it wrong? These aren’t the type of beam shots you wanted?

Hrrmph.

Okay, maybe you’ve got a point. It is a thrower, after all. Here are some photos to show how it actually looks during use, at a distance.

But there’s a blizzard outside right now, so I’m not getting any outdoor shots. The best I can do at the moment is to shine a beam across the inside of my house, and take pictures of the hotspot.

First up, the Emisar D1.

I often keep an Emisar D1 in my purse, because it’s really small in shorty (18350) form and it throws pretty well — easily well enough for most daily tasks. Next to the K1 though, well, it looks a bit weak. I had to turn it up to level 6 (of 7) to get anywhere close to the same brightness as the K1 on level 1.

Top: Noctigon K1 at level 1/7.

Bottom: Emisar D1 at level 6/7.



Clearly, we need to compare it against something more impressive.

The Emisar D1S is more of a dedicated thrower, able to make a beam three times as intense as the D1. It does this by focusing the light into a narrower hotspot.

It fared better than the D1, but it still doesn’t look very impressive. At level 6 (of 7), it was only about as bright as the K1 at level 2.

Top: Noctigon K1 at level 2/7.

Bottom: Emisar D1S at level 6/7.



So let’s go straight to the top, and compare the K1 against the most extreme thrower in my collection.

The BLF GT is a huge and massively overengineered flashlight, designed to embarrass everything else on the market. It’s not what I’d call practical… it’s more along the lines of engineering for engineering’s sake. It’s the “because we can” light which does not ask if we should. So it has a bit of a reputation. It’s also known as “Giggles”.

And the K1 is somehow even more throwy, clocking in at ~685 cd/lm compared to the BLF GT’s 500 cd/lm. The maximum intensity is only half as many candelas, but its beam is otherwise even more intense. Here are the two lights next to each other, with brightness adjusted to match.

Top: Noctigon K1 at level 2/7.

Bottom: BLF GT (smooth ramped to match K1 brightness).



LED and Reflector

To throw this well, a light needs two things: A big reflector, and a teensy tiny LED. This section will examine both.

The teensy tiny LED is called an Osram CSLNM1.TG, better known as a 1mm White Flat. It’s small enough that getting a clear picture of it is a bit difficult:







As for the reflector, it’s big and beautiful and quite photogenic:

Now if you’ll excuse me, I need to go on a quick acid trip. It’s the only way to properly appreciate this reflector.









It also helps that the lens has AR coating… and it’s the good kind which looks orange from the side, not the ugly kind which looks blue from the side (and turns the beam green).

Interface

Basic usage is pretty simple: Click for on/off, hold to change brightness. That’s all you really need to know to use this UI.

But if you want to go more in depth, read on.

The interface is called Anduril, and can do a lot of things. At its core, it provides pretty simple ramping with one-click on/off, but there are also many other modes and configurable options.

The generic manual documents everything in text form, or there’s also a UI diagram to provide a visual reference for most of the available features:

Button LED s

The button has red, green, and blue LEDs under it. These are used to indicate status, depending on what mode the light is in. There are three states, each with its own behavior:

On (all active usage modes)

Off (main LED off)

off) Lockout (UI locked by button presses)

The “on” mode constantly displays the battery voltage, according to this scale:

< 2.9V: black

2.9V to 3.3V: red

3.3V to 3.5V: yellow (red+green)

3.5V to 3.7V: green

3.7V to 3.9V: cyan (green+blue)

3.9V to 4.1V: blue

4.1V to 4.4V: purple (blue+red)

> 4.4V: white-ish (red+blue+green)

This can give reasonably detailed battery charge info at a glance, even during use. The voltage reported will be lower while the main LED is on though, because of battery sag.

The “off” and “lockout” modes can have a variety of colors and patterns, configurable by the user. There are four “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

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.

In standby modes, parasitic drain depends on the button LED configuration:

~0.02 mA with button LED s off (28 years to drain a 5000mAh cell)

s off (28 years to drain a 5000mAh cell) ~0.06 to ~0.12 mA with button LED s on low mode (4.7 to 9.5 years)

s on low mode (4.7 to 9.5 years) ~2 mA with button LED s on high mode (~3.5 months)

s on high mode (~3.5 months) probably about ~0.2 to ~0.4 mA on blinky mode, or 1.5 to 3 years runtime

For comparison, moon mode (the bottom of the ramp):

Moon mode: ~4 mA (~52 days)

Thermal regulation

The Noctigon K1 basically doesn’t need any thermal regulation. It has a high enough mass-to-power ratio that it barely gets warm during use, even at turbo level.

However, thermal regulation is still included, mostly to make sure the driver won’t overheat. The default temperature limit is set to 55 C. It generally shouldn’t regulate during normal use, but it will still reduce power if you run it while wrapped in a blanket or something.

To actually see it do any thermal regulation, I had to give it a relatively high-amp cell and put it in a warm room with no moving air. It never got hot enough that it would be uncomfortable to hold:

This is a pretty normal result for a linear driver. It took 8 minutes to get hot enough for regulation to start, and then it took another 13 minutes to slowly regulate down to a stable level. Eventually the battery voltage got close enough to the LED voltage that it wasn’t burning off extra power any more, and it started regulating back up to keep the temperature steady. Then at the end the battery couldn’t keep up any more, and output dropped due to a low battery.

Power regulation

The K1 driver is regulated at all levels, and should keep the brightness pretty steady as long as the cell voltage is higher than the LED’s forward voltage. So it gets pretty flat output at all levels except turbo. The amount of time turbo stays flat depends almost entirely on the type of battery used. This test shows a Samsung 48G cell, which is among the weakest 21700 cells on the market. Also a Samsung 50E cell, which is a little bit stronger but not by much. A higher-amp cell would stay flat longer.

Here is a runtime graph to demonstrate the overall regulation pattern:

At the end, the blocky step-downs are when low-voltage protection (LVP) activates. It keeps stepping down until it’s at the lowest level, then eventually shuts off. I didn’t wait for it to shut itself off though, because that takes a long time.

The only weird thing I noticed about the power regulation is that the driver can have a bit of difficulty going directly from turbo to moon level. When doing this, the main LED can sometimes turn off entirely for a few seconds before slowly ramping up to moon.

Source Code

… will be merged into the main repository soon. Until then, here’s a K1-specific branch.

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 K1.

Potential Issues

It’s a bit large to carry around daily, but fits nicely in the included holster if you don’t mind wearing it on a belt.

This light is not meant to be used for up-close work. Because it’s a dedicated thrower, the hotspot is small and intense. It takes a few meters for the beam to collimate, and up-close it makes a donut-shaped beam. This is totally normal for throwers, but it may be unexpected for anyone who hasn’t used a long-range thrower before.

Upgrade / Mod Options

There’s not really much to change about this light. It’s already pretty much maxed out.

I guess you could make it less throwy, though, by putting in a bigger LED. But if you want a different LED, I think most of the popular ones will be available as options when ordering. The White Flat version may have been first, but Hank mentioned plans for a few other versions too.

The most obvious ways to modify this light are:

Change the emitters / MCPCB . Intl-Outdoor and MtnElectronics both sell compatible parts.

. Intl-Outdoor and MtnElectronics both sell compatible parts. Firmware changes. This is easy to do if you have a pogo pin adapter, but difficult otherwise.

Summary

What I liked:

It’s almost like having a BLF GT, but at only a fraction of the size, weight, and cost. (the K1 throws two thirds as far as the GT)

GT, but at only a fraction of the size, weight, and cost. (the K1 throws two thirds as far as the GT) Regulated driver, so output is mostly flat and there’s no need to worry about over-driving the LED .

. Even on turbo, it barely gets warm during use.

RGB lighted button. I like this more than front-facing aux LED s.

lighted button. I like this more than front-facing aux s. Built-in charging at 2A.

No rubber cover needed for the USB port.

port. Firmware flashing pads on the driver, for easy updates and customization.

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

The steel bezel is a nice touch.

Things I feel neutral about:

The anti-roll detailing doesn’t line up with the button.

With such a narrow spot, it is exclusively meant for use as a thrower. This light won’t be useful for walking the dog or looking around the house; it’s only used for seeing things relatively far away.

What I didn’t like:

It’s not as small as the Emisar D1S, so it’s not as convenient to carry.

Although the champagne color is okay, I was really hoping for something darker.

The White Flat LED only comes in cool white (~6000K, but with a pretty nice tint).

The End

Or an end, anyway.