Review NITECORE TM20K - 20,000 lm. USB-C

Newly Enlightened
Dec 3, 2012
NITECORE TM20K was sent to me directly by NITECORE for review.


For technical details of the flashlight: is external)
For purchase: is external)
The multilingual manual: is external)

Main features:
• Uses 19 CREE XP-L HD LEDs with a maximum output of 20,000 lumens
• Maximum intensity of the peak beam of 22,200 cd and maximum throw of 290 meters
• Lightweight, rigid and fast cooling tube made with unibody CNC technology
• 2 built-in 21700 rechargeable Li-ion batteries (9,600 mAh in total)
• Intelligent lithium-ion battery charging circuit with USB-C charging port
• Ambidextrous tactical buttons specially designed for tactical activities
• Interchangeable STROBE READY ™ (Patent # ZL201320545349.4) and TurboReady ™ Settings
• STROBE mode uses randomly changing frequencies for stronger dizzying effects
• Highly efficient constant current circuit provides stable output for up to 13 hours
• Integrated advanced temperature regulation (patent n. ZL201510534543.6)
• Optical lenses with scratch resistant coating on both sides
• Made of aircraft grade aluminum alloy
• HA III military grade hard anodized finish
• Waterproof and dustproof classification according to IP68 (2 meters submersible)
• Shock resistant up to 1 meter
• Tail stand capacity

Length: 145.5mm (5.73 ")
Head diameter: 50mm (1.97 ")
Tail size: 50mm × 26mm (1.97 "× 1.02")
Weight: 422g (14.89oz) (clip included)

USB-C charging cable, holster, lanyard
N.B. NITECORE® products can be repaired free of charge within 24 months from the date of purchase. Beyond 24 months, a limited warranty applies, covering the cost of labor and maintenance, but not the cost of accessories or spare parts.



These days NITECORE presented the new TM20K. As assumed by the initials, Nitecore's new powerful Tiny Monster can deliver up to 20,000 lumens with a maximum intensity of 22,200cd, through 19 CREE XP-L HD LEDs, and covers a maximum distance of 290 meters with its beam. TM20K has small and compact dimensions, enough to fit comfortably inside the palm of the hand and has an innovative simple and functional operating system. The construction materials and all the technology adopted for this new Nitecore are remarkable.
TM20K has a CNC Machined Unibody Design, is powered by 2 internal batteries in 4800mAh 21700 format, has 6 light levels over the Turbo and the Strobe with a maximum autonomy of 13 hours.
TM20K has 3 push button switches and 1 toggle switch for managing levels, mode of use or lock. It has a residual charge indicator and memory of the last level used.
Nitecore TM20k has IP68 certification (2m submersible) with an impact resistance of 1 meter and is supplied with a large and resistant CLIP and a practical magnetic closure holster.
TM20k is an ideal companion for night outings in particular for research, camping, use in industry and law enforcement.


comes in a "premium" rigid cardboard box, protected by a shaped foam.
On the box, in addition to the photo, there are technical details of the new Nitecore and serial number.
Inside the package we find the Nitecore TM20K with the Clip inserted, a rigid holster, a USB-C charging cable, a lanyard, the user manual (multilingual) and a card with photos of some of the previous Tiny Monsters produced by Nitecore in these years.


The glass of the Nitecore TM20K comes with a protective film to be removed before use and, tied to the clip, a label with the warning to put the flashlight in the holster with the block inserted.

NITECORE TM20K, as soon as it is picked up, immediately returns a sense of robustness and excellent surface processing with good finishes and thicknesses. I have rarely seen this quality in other flashlights. The processing is perfect without sharp edges or processing residues. TM20K is compact, fits well in the hand and has ambidextrous tactical buttons. It is 145.5mm long and weighs, according to my scale, 426g with the clip inserted. The writings are clearly legible and placed in the right places.


Nitecore TM20K is built in aircraft grade aluminum alloy and made with unibody CNC technology, which gives the torch excellent heat distribution and durability, with a black, semi-gloss, hard military grade HA III anodized finish.
TM20K has tail stand capacity.


On the head of the NITECORE TM20K we find an optical system consisting of SMO reflectors and 19 CREE XP-L HD LEDs, with a maximum power of 20,000 lumens, and optical lenses with anti-scratch coating. The LEDs are well centered and the bezel, in burnished steel, is slightly crenulated. The TM20K has a deep reflector in the center for the launch, while laterally, around, we find 18 LEDs for the totally flood beam.


Also on the head we find numerous cooling fins to mitigate the heat produced.


The body with the tail of the TM20K has a rectangular shape with space for 2 cells in 21700 format. This form factor reminds me in particular of the Fenix LR35R released in 2020. The rectangular shape and the small dimensions make it easy to grip with the hand and of course they exclude rolling.
On the sides we find a diamond-shaped knurling that improves the grip with the hand.


On the body we find, screwed with three torx screws, the supplied clip. Large size allows excellent portability on jeans in the belt or pocket, for attachment to the backpack and the MOLLE system.


The care with which the Nitecore TM20K is built can also be seen from the details such as the small gasket, on the Clip, near the holes where the 3 screws are inserted.


On the bottom side is the user mode selection switch and on the opposite side the mode button that we will use to change the available brightness levels.

The user mode selection switch has 3 positions:
1- Torch lock. We put the lever on the lock icon to access the Lock Mode.
In block mode we cannot use the flashlight. Nothing happens when you press any button; I find this very practical solution to avoid accidental starts.
By entering Block Mode with the flashlight on, it will automatically turn off and enter Block.
In my sample, received for the review, to unlock the flashlight just move the lever to the desired position 1 or 2 (the sales package, as written in the manual, should have another procedure for unlocking the flashlight once the it is locked).
2- Daily Mode (Mode 1). All brightness levels and special modes are available. The Power button gives access to constant lighting (just press it once to turn on the flashlight and press it again to turn it off).
3- Tactical Mode (Mode 2). The Power button gives access to momentary lighting (the flashlight remains on as long as the button is pressed) of the previously stored brightness level or special mode.


The slightly raised mode button is used to change the available brightness levels and is located above the charging port. It has excellent accessibility remaining in the upper part of the socket.


In the flat bottom of the TM20K we find the power button with a blue LED in the center, remaining charge indicator, the tactical buttons and the USB-C charging port. The tactical buttons are ambidextrous specially designed for tactical activities.


Battery and Charging:

The power supply system
of the TM20K consists of 2 batteries in the 21700 format of 4800mAh, for a total of 9600mAh, integrated and not replaceable by the user.
Some information on the batteries used can be read once the clip is removed.


NITECORE TM20K has a USB-C charging port and allows charging in both standard mode and quick charge (QC) mode.


The charging time in QC mode, as measured by me, is about 4 hours and 30 minutes (12.6V / 1.6A max).
According to Nitecore, when the TM20K is fully charged, the standby time is about 12 months.




Despite the 3 push button and 1 toggle switches, the management of the flashlight is not particularly complicated.
The Nitecore TM20K has 6 light levels plus Turbo and Strobe.

At the bottom of the TM20K we find the round-shaped metal power button, to turn on the flashlight constantly (Daily mode) or momentarily (Tactical mode). TM20K has memory function. When reactivated, it will automatically enter the previous stored brightness level or special mode.
In Tactical Mode we can choose the desired level by briefly pressing the Mode button while holding the Power button to scroll through the following brightness levels: ULTRALOW - LOW - MID - HIGH.

At the bottom side is the Mode Button for a quick selection of the desired user mode between 4 levels of brightness plus diffused light (floodlight) and depth light (spotlight). This is the sequence:
When the light is on, to go into the special Floodlight and Spotlight modes, you must press and hold the Mode button. Then release to select the desired special mode or briefly press the Mode button to return to the previously stored brightness level.

TM20K is equipped with 2 tactical buttons, with ambidextrous activation, which are used to activate the Turbo (TurboReady) or the Strobe (StrobeReady). The default is TurboReady.
When the light is on or off, press and hold one of the tactical buttons to access TURBO or STROBE. Release to return to the previous state.
Briefly press the Mode button while holding one of the Tactical buttons to switch between Turbo and Strobe.

Charge Indicator:
When the light is off, in Daily Mode (Mode 1) / Tactical Mode (Mode 2), short press the Mode button and the power indicator will flash to show the battery voltage (± 0.1V).
ATR (advanced temperature regulation):
Integrated ATR technology adjusts the TM20K's output based on working conditions and the surrounding environment to maintain optimum performance.

Nitecore TM20K next to other flashlights.


From left: Acebeam X80 - 25000LM, Imalent MS08 - 34000LM, NITECORE TM20K - 20000LM e Olight X7 Marauder - 9000LM


The beam
of the Nitecore TM20K has good uniformity with diffused lighting with a wide radius and a not particularly cold color but tending to yellow in the first part of the crown / spill. The spot has a white light and is clearly visible with a color temperature, measured by me, of about 6500K / 6600K.
The Low, Mid, High and Turbo levels use all 19 LEDs on, while the Ultralow level uses only the central LED (Spotlight) lighting.
To the eye I don't see any significant PWM in any of the 6 modes. The beginning of the spill is adjacent to the walkway, considering all 19 LEDs on.
In the evening test, in the dark, I appreciated the large angle of illumination available to the TM20K; the distance covered by the beam is discrete, allowing good illumination at small and medium distances.



Some values measured with the OPPLE Light Master:
CCT (color temperature): ≥ 6500k
Ra or CRI (Color Rendering Index): 72
The flicker (flicker index) has a non-risk value.

The Runtime were done in a closed environment with an ambient temperature of about 20 °C with the internal batteries of the TM20k fully charged. The numerical values in "Candela", taken with the aid of the LX1330B Luxmeter, are equal to or higher than those declared by the parent company.
I would like to clarify that the values expressed by the graphs must be taken, above all, as a reference because they are made with means and environmental conditions different from those used in the laboratory.
Starting from the brightest level, the TURBO (20,000lm), in my tests the duration is 6 or 7 seconds after which it goes down to High brightness (3,100 lumens). The turbo can be recalled for a long time but the duration and light power varies according to the time elapsed between one activation and the next, the temperature and of course the state of the batteries. Let's see in the graph of the tests done in the first 5 minutes.


At the end of the test, which lasted 5 minutes, I took an image with the FLIR thermal camera. As you can see from the photo, the temperature values in °C are quite high even if we must consider that they were taken in a closed environment, without ventilation, and activating the maximum brightness (Turbo) of 20,000 lumens several times.
Another shot was taken after 7 minutes with the Mitecore TM20K in High mode (3,100 lumens). Here the temperature values in °C are naturally lower.


High, Medium and Low Levels.
Starting from over 23000cd, of the High level (3,100 lumens), after 8 minutes there is a sudden decrease in brightness until it settles at a value, in candles, halved compared to the initial one. This trend is constant for over 3h20min after which autonomy slowly runs out.
The Runtime trend of the Medium level (1,900 lumens) is similar to that seen for the high level, but the initial sudden drop occurs 18 minutes after switching on, then maintaining a constant brightness up to over 3h38min before starting to go down and then to switch off shortly after 4 hours of work.
The Low level (1,050 lumens) has a constant trend for about 4 hours before starting the descent that leads to the TM20K switching off after 4 hours and 26 minutes.


Another test was made by placing a small fan next to the TM20K. The level set is the High level of 3100 lumens. You can see from the graph how Nitecore's ATR temperature control system works.
With the cooling caused by the fan there is a higher light output but at the expense of the working time (runtime) of the TM20K.




Nitecore TM20K
is the new torch of Nitecore's Tiny Monster series. It has an excellent construction with compact dimensions and a lighting power that reaches the remarkable brightness of 20,000 lumens in Turbo.
TM20K is a tactical flashlight built with unibody CNC technology with an ambidextrous control system (UI). It has 6 light levels besides the Turbo and the Strobe (both quick access).
TM20K has 3 push button switches and 1 toggle switch for managing levels, mode of use or lock. It has a residual charge indicator and memory of the last level used. Charging takes place via the USB-C port while the batteries (2x21700) are internal and not accessible by the user.
In my opinion, the brightness is managed well between the various levels although I would have liked a low level with less lumens. The beam it emits in addition to being remarkable in TURBO also has an opening angle of almost 180 °, really impressive.
Good runtime and temperature management through Nitecore's ATR technology.
In conclusion, I really liked the Nitecore TM20K. I particularly appreciated the excellent build quality and attention to detail. Beautiful and complete the sales package where we find everything you need to immediately use the new Nitecore Tiny Monster. Thank you for reading the review.

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