Thrunite TH20

2 years ago written by

I received the Thrunite TH20 NW from Thrunite.com for the review.

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The TH20 is a headlamp with a reflector and infinite brightness settings, powered by 1xAA or 1×14500 battery. The headlamp is available in CW and NW version. I asked and got the NW version.

• LED: CREE XP-L V6 LED with a lifespan of 20+ years of run time.
• Mode & Runtime (Tested by one Eneloop AA 2450mAh NIMH rechargeable battery):
• -Firefly (0.3 lumens, 14 days)
• -Infinity Low (1.6 lumens, 21 hours)
• -Infinity High (230 lumens, 95 minutes )
• -Turbo (250 lumens, 93 minutes)
• Batteries Applicable: 1x AA battery, 1x 14500 battery.
• Working voltage: 0.9-4.2 V.
• Reflector: Orange Peel.
• Peak Beam Intensity: 1120 cd
• Beam Distance: 67 m (max.)
• Dimensions: 70 mm * 24.5mm
• Weight: 76g (without battery).
• Waterproof: IPX-8 (2 m)
• Impact Resistance: 1 m.
• Material: Aircraft grade aluminum body with premium type III hard anodized anti-abrasive finish.
• Accessories included: O ring, spare rubber slot.

The TH20 comes in this cardboard box.

Inside you’ll find the TH20, manual, headband with light holder, spare headband and spare o-rings.






The light is compact, and has an anti-roll design.


It has a small reflector with light orange peeling, and glass with AR treatment are above an XP-L NW emitter.

The light is held on the headband by a silicone holder that allows the light to rotate


On one side of the light you have an electronic switch

On the other side: the tailcap. There’s a milling in the battery compartment to avoid batteries being stuck in the light by the vacuum produced when removing them. Even without the milling there’s a lot of room for batteries


Tailcap has a golden spring, threads are square cut and anodized so physical lockout is possible. It is flat so the light can tailstand.

At the positive pole there is a physical protection against polarity inversion (so only button top batteries).

User interface
From off a single click turns the light on and off.
From off keep pressed the switch to turn the light on at firefly mode.
A double click gives you turbo mode. Another double click gives you SOS.
When the light is on, keep pressed the switch to increase the brightness with a logarithmic scale brightness increase; release and keep pressed again to decrease the brightness in the same way. The light can be set from the lowest infinity setting to the infinity high. When you reach lowest and brightest settable output, the light will blink twice.
Using a stopwatch I measured about 5” to get from the lowest to the highest setting.
When the light is on keep pressed the switch to return to firefly mode.
Light has memory mode for your customised brightness, not for turbo, firefly or SOS.

Beamshot
Weather is bad, so no outdoor Beamshots.
The small reflector and the big LED give a rather wide beam, with a defined spot.





The fog and rain gave me a brief window at 1 am so I took the change and made a quick beamshot to show how close the spill is to the walking plane (the space where your feet hit the ground when you walk).
I have a lot of background light in this setup so this first pic is with the TH20 off. Nothing crazy, but many 5000K LED streetlamps do their job, and you can still see the street pavement.

And this is with the TH20 on. The spill on the TH20 starts kind of close to the feet, but there’s still some distance.

Output and runtime




I had a timer to avoid over discharging the 14500 unprotected battery. When the test was interrupted the resting voltage of the cell was 1.84 volts. So, avoid unprotected batteries with this light.

My thoughts

  • This light is well built and finished.
  • Output is good for an AA battery, and the tested levels are regulated. The output at turbo will increase when using a 14500 battery, unfortunately unprotected cells needs to be used with great care otherwise they will be over discharged (on turbo mode it passes from full brightness to overdischarged in less than 3 minutes); while you can get full brightness without worrying about overdischarge with protected batteries.
  • The UI interface matches my needs: direct access to a low mode, turbo mode, last used mode (except low and turbo), which means that I can use the light at my customised settings, and go back to firefly or turbo without losing my customised brightness level.
  • The brightness changing system works fine, but I’d like to add a blink when it reaches 50% of the settable brightness (on the Armytek Predator it blinked every 25%), just as reference.
  • The brightness varies with a logarithmic pattern (I have not way of testing this), preferable to a linear way for the needs of the human eye: at small output, where the eye has greater sensitivity and can detect easily small output variations, the brightness changes slowly; at higher output, the brightness increase will be faster, as the eye has much smaller capability of detect output variations.
  • One thing that contributes to the ease of use is the switch. It is an electronic switch with a great tactile feedback, a big and grippy switch cover, and the switch works even if pressed on the side of the switch cover, even if you press in a diagonal way.
  • The headband and light holder work fine.
  • This headlamp, having a reflector, is suitable for people who look for a bit of throw for their need, since it will throw further than other models without reflector or with diffusing optics (relatively speaking, since the big LED and the small OP reflector, will give you some focusing to the LED).
  • The tint of my sample has a visible greenish colour. I tested 2 Thrunite lights with NW tint so far, and all had good NW tint with a pleasant yellow colour, so I believe I got an unlucky sample.
  • The light could benefit of a clip since this light could easily work as an EDC, as well as a magnet in the tailcap, to provide directional lighting without the need of the headband.

Thanks to: AntoLed for the luxmeter and the camera advices.

Article Categories:
14500 · AA · Headlamp · THRUNITE