Thrunite TC20 V2

Like the original TC20, the V2 carries forward the trusty Cree XHP70 gen 2 emitter. To be honest, there aren’t many emitters on the market as versatile as this one. The XHP70.2 is a 7×7 mm quad-die LED running on 6 or 12 volts Thrunite gives you a choice of two tints; neutral white or cool white. Mine came in cool white, which although not my preferred tint, is better for output. I think this emitter is perfectly suited to a single-cell compact light because when paired with a good quality boost driver, it’s efficient and capable of high output at modest drive currents so it runs cool. 

The LED is paired with an aluminum orange peel (OP) textured reflector topped with a toughened mineral glass lens with AR coating for maximum light transmission. The bezel is matte finish and looks like stainless steel. It’s not crenulated, so you won’t know if it’s turned on if you set it bezel down. I will say it looks slick with the black finish, matte switch, and bezel. Thrunite could have gone with a shiny bezel, but the matte finish looks much better in my opinion. 

Thrunite did a good job matching the LED to the reflector. The beam is expectedly floody, but has a good amount of throw. The large hotspot is diffused with a smooth transition from spot to spill thanks to the OP reflector. The XHP70.2 throws out a wall of cool white light, and I was pleasantly surprised with the uniformity of the beam. However, the price of admission to the XHP party is paid with corona and tint shift. The OP reflector helps, but it’s still there and noticeable even when not white wall hunting.

• Length: 11.9 cm / 6.85 inches
• Head diameter: 4.2 cm / 1.65 inches
• Body diameter: 3.35 cm / 1.31 inches

Weight: 

• With 5000 mAh 26650 battery: 242.6 grams / 8.55 oz. 
• Without battery:143.2 grams / 5.0 oz.

Flashlight comparison

Left to right group 1: Thrunite TC20 V2, Astrolux EA01, Astrolux EC03, Thorfire C8.

Group 2 left to right: Thrunite TC20 V2, Lumintop FWAA.

The TC20 V2 employs a constant-current boost driver to step the 4.2 volts from the battery to the 6 volts for the XHP70.2. It’s a great combination for output and efficiency. You can get high output at modest drive currents for sustained output without generating tons of heat or voltage sag on the battery. 

The UI is delightfully simple and well thought out. It’s perfect for a general purpose light like this.

Modes: Firefly, low, medium, high, and turbo. There’s a semi-hidden strobe mode also.

From OFF:

• Press and hold: Firefly mode
• Single click: Turns on in last mode
• Double click: Turbo
• Double clicking again in turbo switches to strobe

From ON:

• Press and hold: Switches to next mode L-M-H-L
• Single click: Turns off
• Double click: Turbo
• Double clicking again in turbo switches to strobe

Mode memory:

• Yes, last mode memory

Low voltage warning:

• Yes, the switch indicator will flash red when the battery is at 3-2.8 volts. The light will turn off when the cell voltage goes below 2.8 volts. From the manual: 1-10% flashing red indicator, 11-20% solid red, 21-100% solid blue.

Strobe/blinkies

• Single strobe at about 3 Hz

Lock-out mode: 

• None. Unscrew the head ⅛ turn to manually lock out.

PWM

•  None.

Additional info: There’s just something about a simple UI that’s refreshing to me. Don’t get me wrong, Anduril’s great, but a flashlight should be easy to use for non-flashaholics, and amongst the complicated UI’s we’re getting these days, it’s nice to see Thrunite implementing a very useful UI in the TC20 V2. The single strobe is pretty hidden so you won’t be accidentally activating it. The mode spacing combined with a true sub-lumen mode is icing on the cake. The mode cycling speed is a little slow for my taste (about a 1 second pause between), but this really is a light anyone can pick up and use without fretting over turning it on or changing modes. The TC20 V2 features Thrunite’s version of temperature regulation, and it really works great, much like the sensor in Anduril, except this one’s fixed at about 50 C. This means the light shouldn’t get too hot to handle.

The V2 uses the same 26650-size battery as the first version. Like the original, the TC20 V2 comes with a Thrunite-branded high discharge 5000 mAh protected flat top 26650. I measured it at 69.3 mm long. If you want a spare, Trunite also sells this battery separately. It’s nice to see that this isn’t a proprietary cell, and any flat top or button top 26650 will work in the TC20 V2. I tried a Wurkkos-branded button top 26650 and it fit fine. The protection circuit is properly beefy. I tested this battery in my FT02S and it easily pulled 25 amps for several seconds without tripping the protection circuit.

The V2 retains the onboard charging, but instead of micro USB, the V2 now features USB type C charging. This is a major upgrade from the dated micro USB and Thrunite specs the charge current at 2 amps. On my 2.1 amp wall adapter, I got 1.92 amps with a nearly-drained battery. The onboard charging should recharge a flat battery in around 2.5 hours, which is pretty quick! Yes, you can remove the head and keep it plugged into a charger and use it, albeit at significantly reduced output.

I’m pretty amazed at the output figures we’re getting from small lights these days, and I’m expecting great performance from the TC20 V2. Thrunite promises a modest performance upgrade from the original, so we will see how it does. 

Amp measurement  

It’s hard to trust current figures from a boost driver since it’s not the actual output current to the LED. What you see here is the input current from the battery, but here we go:

• Firefly: 2 mA
• Low: 80 mA
• Medium:500 mA
• High: 3.12 A (3.85 A at turn on)
• Turbo: 10.30 A (10.50 A at turn on)

Parasitic drain:

• 0.16 mA.

Runtime graph

I conducted the runtime test using the 30-centimeter integrating sphere with the Digi-Sense 20250-00 data logging lux meter. I used the fully charged Thrunite 26650 battery and tested all modes (except strobe, low and firefly since they run for days and days…ain’t nobody got time for that). 

Turbo mode started at a little under 4000 lumens, which is pretty good for a small light. The stepdown happened within 5 seconds to 3220 lumens, with gradual decreases over the next 3 minutes. The light holds 3000 lumens or better for over 2 minutes. Not bad. I didn’t notice any significant heating until about the 30 second mark, around 25 C over ambient. The output dropped to under 2000 lumens by the 3 minute 25 second mark, and held that for 6 minutes, followed by slight stepdowns over the next 15 minutes, until settling at 1050 lumens for the next 1 hour 15 minutes. The last 24 minutes of the runtime consisted of gradual stepdowns, with a hard shutdown at the 2 hour mark. Thrunite says 220 seconds + 90 minutes for the runtime (that’s 1 hour 33 minutes 6 seconds). If you aren’t paying attention to the LVP indicator light on the switch, you’ll be in for a surprise because the output was still over 500 lumens when the light quit. Temperatures got up to 56 C at the head and a reasonable 50 C at the battery tube. 

High started off at 1869 lumens, which lasted for several seconds before slowly tapering off. The output is still holding over 1850 lumens for the first 30 seconds, and after 5 minutes the temperature is 52 C and the output is holding steady at 1785 lumens. That’s pretty impressive, but more impressive is the sustainability. The light holds 1700 lumens for almost 17 minutes, and only steps to under 1000 lumens at the 1 hour 55 minute mark. Here, the output takes a steep dive and tapers off as the LVP indicator starts flashing red. The light runs for another 7 minutes before the driver pulls the plug and the light shuts off at 2 hours and 2 minutes. Thrunite specs 2 hours 22 minutes for the runtime, so close enough. 

Medium started at 322 lumens and in true boost driver fashion, held that output forever. Well, it seemed like forever, since the output didn’t drop below 300 lumens until 8 hours and 58 minutes into the test. For the next 19 minutes, the output steadily dropped as the battery voltage drained until the 9 hour 17 minute mark when the light shut down with the same abrupt cutoff as high and turbo. The only indication you get that shutdown is imminent is the flashing indicator light. I didn’t notice any remarkable heating in the light during the run, maybe 5 degrees above ambient. Thrunite specs 9 hours for the runtime, so again pretty bang on. 

Some observations: Since this is a boost driver, it only pulls as much current as it needs for the duration of the runtime tests to keep a steady voltage to the LED. With a stout, high capacity battery, that means long runtimes and consistent output. It seems the protection circuit on the battery is set to 3 volts since the battery was around 3 volts after each test. Overall, the TC20 V2 has a nicely tuned boost driver and works really well with the LED. The runtimes are close to the factory specified, which is nice. I didn’t observe any wild fluctuations in output or see-saw behavior from erratic temperature regulation either. This flashlight will guarantee long runtimes and consistent output, all good things and a testament to careful engineering in my book. However, I didn’t like the abrupt cutoff with no visual warning (other than the indicator light), nor the fact the light was deader than Jimmy Hoffa and non-functional after the tests. 

Lumen measurements (for each mode)

For the lumen tests, I used my home made 30 cm integrating sphere calibrated with a light of known output using the Digi-Sense 20250-00 data logging lux meter. I used the included fully charged 5000 mAh battery. Readings were taken at 30 seconds. I captured the turn on reading for turbo.

Firefly mode was too low for the Digi-Sense to measure, which tells me it probably is sub lumen, or at least close. Overall, this is very good performance from a compact light! Very versatile mode spacing with a very wide range of brightness at your disposal. I’m a little under Thrunite’s turbo spec, but the other readings are on point and more importantly, consistent.

Throw numbers: 

Throw was measured at 5 meters indoors using the Uni-t UT383S lux meter. I used the included Thrunite 5000 mAh battery for all tests. Readings were recorded at 30 seconds.

Again, Firefly was too low for the Uni-t to measure. Thrunite only listed a single ‘max’ throw figure in the literature, probably turbo. I was not expecting this much throw from a reflector smaller than a C8. This is more fantastic performance from the TC20 V2 and goes to show that even after all these years, the XHP70.2 still has the right stuff.

I compared the TC20 V2 to the Astrolux EA01 and a Thorfire C8 with a 6000K XHP50.2 3 volt, at around 3200 lumens.  

• Outdoor shots: The fence is about 40 meters away. We can see the TC20 V2 is the flood winner, but still has decent throw. EA01 is the obvious throw winner, with the C8 not far behind. I think for general purpose use, the TC20 V2 is still the best.