ThruNite TN12

DSC_9673 DSC_9674

ThruNite started a few years ago with a small light, then they added a very good thrower (Catapult) and has lately added lots of other lights to their range. The light I am looking at here is a compact light in 18650 size. The light has 4 brightness settings and a strobe, to change between them the head must be twisted loose then tight. On/off is done with a forward tail switch. The light is made of aluminum with hard-anodized (Type 3) finish.

DSC_9562 DSC_9563

The light is delivered in a cardboard box with a window and some FL1 specification on the outside


The box contains the light, 2 extra o-rings, lanyard, split ring, extra rubber boot, extra switch, holster and a instruction sheet.

DSC_9566 DSC_9567 DSC_9568

The light uses a LOP (Light orange peel) reflector with a XM-L led in the center. The bezel has a light crenellation.


The head has some faces on it, they give a little grip when changing level, but do not work as an anti roll device. There are no cooling fins and with this small head it will be difficult to get rid of all the heat, as can be seen later ThruNite has a fine solution for this.


The user interface is simple, just loosen and tighten the head to select next setting. The light is with memory and will remember the last setting used. My copy of the light had a serious problem with mode skipping, i.e. it might jump more than one step forward for each loosen/tighten sequence. A cleaning solved this problem.


The backside of the head shows the connection to the battery that is reinforced with a metal plate, this makes it possible to use flat top batteries in the light. The golden ring at the periphery was the part I had to clean, together with the threads to make the mode change work.

DSC_9576 DSC_9577

The battery tube has square cut threads and o-rings to seal the light. The tail thread is anodized, making it possible to lock out the light.


On the body is a knurling with a good grip.


Inside the battery tube was a extra plastic tube, making it possible to use 16340 batteries with very little rattle.

DSC_9574 DSC_9572 DSC_9677

In the tailcap is the usual spring. The switch is mounted lower than the two ridges, making it possible for the light to tail stand.
With a split ring mounted in one of the holes, it is possible to use the lanyard.

DSC_9582 DSC_9583

A holster is supplied with the light.


Here is all the part the light can be disassembled in without tools.

The light is a slim and light weight, making it a good EDC (every day carry) light and it can put out a lot of light. A forward switch, that does not change modes is a nice feature. The thermal limit is a good safety feature and it does not do anything before the light is very hot, I like it this way. I would have preferred a brighter medium level and full performance on a single 18650 battery.

Technical specification and measurements


The light is rated for use with 1x18650 or 2x16340 LiIon batteries, but not for CR123 (A look at the runtime explains why). The light works fine with all 18650 batteries from 65 to 70 mm long, but some 16340 batteries are to long for it.

Measured size and weight:
Length: 117 mm
Diameter: 21 mm to 25.5 mm
Weight: 97 gram with 2x16350 and 107 gram with AW18650-26.

The light uses a Cree XM-L led.


In the above table I have collected all modes, measured at 3.7 volt (i.e. with one LiIon batteries). All the estimated runtimes are with a 18650 LiIon battery. The estimated lumen is scale from the specified maximum, measured at 7.4 volt.


The first voltage sweep is done in high mode, the light has stabilization down to about 4 volt, this means that it reaches full output with a fresh LiIon battery, but will immediately start to drop in output. The spike just below 3 volt is a battery low warning.


Medium is much lower than high and stabilizes better (maybe this has something to do with less heat), with the lower current it can also keep the light stabilized down to 3 volt.


Low does also have perfect stabilization.


I had to try 2xCR123 in the light, but they did not like the high current draw, as can be seen they lasted less than 10 minutes, before output dropped.
16340 did better, they could keep full output for 18 minutes. With 18650 the light cannot sustain full output, but does keep a good output for 76 minutes.


To see how this light handles the heat, I did a run on my test bench with a temperature sensor on the light. As expected the brightness drops slightly when the led gets hot. The body does get very hot, but something happens at 35 - 37 minutes, the output is reduced, the current drops and the temperature is going down again. This looks as some sort of thermal sensor in the light, that is reducing output due to heat.
Note: My test does not simulate actual usage conditions, but are done on a test bench with only the head of the light and no cooling airflow, i.e. the light will get hotter than during normal use.


With higher voltage the power in the light is greater and the temperature will rise faster. The led gets hotter here, but when the body reaches 60 degree centigrade the output is reduced.


The strobe is 9.8 Hz with 46% duty cycle.

The light does not use pwm and only has a small amount of high frequency noise in the light.

Comparison to other Flashlights

ThruNite TN10, ThruNite TN12, ThruNite Scorpion:
DSC_9626a DSC_9627a DSC_9628a

Sunwayman V20C, Fenix TK21 U2, Olight M21-X:
DSC_9629a DSC_9630a DSC_9631a

For the full comparison to other lights with graphs and beamshots see here


The light was supplied by ThruNite for review.