Nitecore T4K Rechargeable Torch 4000 Lumen Turbo Super Bright Small Flashlight, Protective Case Included

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With the torch both off and on, press and hold the MODE button to access the TURBO level; release the button to switch off or to return to the previous light level set. In the highest turbo mode I measured 465 lumens at turn on, 462 lumens after 10 seconds, 458 after 30 seconds, and dropped to around 220 lumens after 2 minutes where it remained for the rest of my measurements. In turbo I measured 1785 lumens at turn on, 1744 lumens after 10 seconds, 1673 lumens after 30 seconds and it dropped sharply to 520 lumens after 80 seconds. It held this constantly for the remainder of the test. Turbo is accessed with the light on or off by holding the mode button down and is a momentary function that will return to the previous state once the mode button is released, or once the countdown timer on the screen ends. The length of the countdown timer will vary depending on how hot the torch is, and will be shorter if the torch is already quite warm. Ultra-low can be instantly accessed while the light is off by holding down the power button. The Nitecore T4K keyring light has an incredible maximum output of 4000 lumens from the 4 x Cree XP-L2 V6 LEDs and is powered by a built-in, 1000mAh li-ion battery. The flashlight is rechargeable via a USB-C port at the base of the torch and comes with a USB-C to USB charging cable.

Lux Meter: For lumen readings and runtimes, an Adafruit TSL2591 connected to a Raspberry Pi running Ubuntu, using RuTiTe by bmengineer in a custom sphere (build document coming soon, when I have some more time). A UNI-T UT383S is used for candela readings. An Adafruit MCP9808 rounds out the list for temperature monitoring. No other flashlight can compare to the power of the T4K, which is able to output 4,000 lumens while easily fitting inside your closed fist. That’s as bright as the high-power headlights on your car. The T1S uses a Luminus SST-40 LED behind a TIR lens and has pretty good throw for a tiny torch with a noticeable hotspot – around 184 metres or 8460 candela in turbo mode.A tiny OLED display on the unit’s face shows lumen values, mode setting, and time until the battery needs a top-up. This useful little screen takes the guesswork out of which mode you’re using. Additionally, having at-a-glance info on charge is helpful to avoid unexpected dead batteries. With the torch on holding the side switch turns on strobe, a single press turns it off. All modes are memorised – and you can tap the tail switch to momentarily turn the light on until you let go. Mode spacing appears to be progressively brighter to the eye and the modes are well spaced enough to be able to know which mode one is currently in. With that in mind, TLR tend to view mode spacing as battery life indicators (amount of runtime left) rather than the specific output (lumens). I measured the colour temperature as a cool 6507K but with a very neutral tint and a decent CRI of 70. The Nitecore T4K can be turned on and work while charging or remain always on using a USB device such as a power bank (Turbo excluded).

The OLED display is a fantastic feature because you’ll never be left wondering how much time is left before the battery dies. For each brightness level, the display shows a real-time countdown of the minutes left on that level. Brightness modes and max runtimes When in daily mode the light will stay on until you press the power button to turn the light off. To switch between daily and demo mode, simply hold both the power and mode buttons down at the same time until the light flashes once to indicate demo mode or twice to indicate daily mode and the screen will also display the selected mode. As we can see from the graph below, I did some tests on and off with the T4K in Turbo mode for about 10 minutes with the T4K fully charged at 4.20V. The beam of the Nitecore T4K has a not too cold white tint and no particular artifact or dominant. The beam is alluvial in nature but in any case the "HIGH" level of 200 lumens allows a good view during the walk. Instead, leave you amazed by the large amount of light (4000 lumens), even if for a few seconds, of the Turbo level.To put that in context, that old Mini Maglite you have in your drawer weighs over 100g, is almost 15cm long and has an output of around 15 lumens, similar output to your smartphone torch but with a longer range!