Review with X-ray image: Thorfire TK15S (18650, XP-L2, 1050lm)

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stephenk
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Review with X-ray image: Thorfire TK15S (18650, XP-L2, 1050lm)

Disclaimer

The Thorfire TK15S was sent to me for review by Banggood. No other payment was received for this review, and I do not make any commission from links or sales.
Product page: https://goo.gl/xVjKP6
$15.99 with code: a0f9a1

Introduction

Thorfire have made quite a name for themselves recently with an improving line up of quality budget flashlights. The TK15S is an 18650 tube light, using an XP-L2 emitter, side and tail switch with momentary function, and claimed to reach 1050 lumens. In a market with lots of competitors, lets see how it compares?

Packaging

The Thorfire TK15S arrived in a cardboard box, which was thankfully well wrapped by Banggood in foam packaging, as it looks like it met an Elephant in transit. The package contains the flashlight, a clip, 2 spare O-rings, and the instruction manual. The instruction manual is well written, but with a few typos (“flashlight” spelt as “ashlight”). There is no lanyard, which is unusual these days.

Construction

The TK15S is an 18650 tube light (24mm head), with a tail cap that can be removed for battery insertion. There are two buttons, side switch for mode changing near the head, but not too close, and indented slightly to reduce the chance of accidental activation. The other switch is at the tail and used for on/off and momentary. User interface will be discussed in the next section.

The bezel is smooth, which I like. I’m not a fan of the pointless “attack” bezels that are found in many “tactical” lights, as if you are at the point where you need to defend yourself with a flashlight, you are in deep trouble!

A clip attaches to the tube near the tail cap, which is required to stop rolling. The knurling on the grip feels just right. The light can tail stand if required. Construction quality appears to be very good, with quality anodisation, and everything functioning correctly. The lens and reflector were not perfectly clean though – please take note Thorfire.

There are springs as both ends of the battery tube which allows for flat top unprotected batteries. Protected Sanyo/Panasonic GA cells (Blazar 3500mAh raised top 18.65mm x 67.3mm) fitted with no issues. In fact there was some wiggle room, so most “obese” protected batteries should fit. Reverse polarity detection was tested to work. There is low battery warning (light flashes below 2.8V), but low battery protection/cut-off is not documented, thus I would advise using protected batteries in this light that can handle more than 4A current. (e.g. protected Sanyo NCR18650GAs). I wasn’t game to ruin an unprotected cell to test for low voltage protection!




User Interface

There are two switches. The side switch is used to cycle through modes in the order:
Moon>Low>Mid>High>Mid>Low>Moon.
I really like this up and down mode order as it avoids the sudden drop from high to low (or vice versa). The light has mode memory, so will remember the previously used mode (including strobe and bike) when turned on, or momentary used.

Double click when on will access strobe mode which varies between two frequencies (?5Hz and 10Hz). Long press when on will activate bike flash mode, which has 3 higher brightness bursts each second. Single press will return back to the previously memorised mode, or turning off will memorise the flashy mode.

The forward-clicky tail switch allows for momentary, and on/off. This is very useful if you want a short burst on light, and being able to use momentary in any normal mode (not just high) is very useful for some specialist uses.

Being into light painting photography, I really like this user interface due to the ability to easily switch between high and strobe and back again, memory mode, and ability to use momentary for any memorised mode. The video below shows the user interface:

The light can be physically locked out by slightly unscrewing the tail cap.

Output, Runtimes, and Beam

The outputs and runtimes are as follows (measured using protected Sanyo NCR18650GA 3500mAh):
HIGH
Claimed – 1050lm 50min
Measured – 1100lm@30secs, 1050lm@2.5mins. Note: 3min step-down timer
Runtime theoretical, as heat would prevent continuous test.
MED
Claimed – 500lm 50min
Measured – 500lm@30secs, 450lm@29mins, 200lm@4hr, Note: 30min step-down timer
After 4hrs 20mins runtime (returned to medium mode immediately after each step down), battery voltage was 3.22V, with subsequent 3023mAh charge. Thus >5hrs runtime may be possible.
LOW
Claimed – 100lm 5h
Measured – 50lm@30secs and 30mins.
Runtime still to be tested, but will be far more than claimed figure.
MOON
Claimed – 1lm 360h
Measured – 1lm @30secs and 30mins.
Runtime to be tested when I have a spare fortnight!

The high mode steps down at 3 minutes to medium. The medium mode steps down at 30 minutes to low. Both of these step downs are timer and not voltage controlled, and thus it is possible to immediately step back up if required. Whilst I’m personally not a fan of automated step downs, 3 minutes is usually sufficiently long enough for most requirements to be kept on high. The step down will reduce the likelihood of the light getting too hot in the wrong hands or if left unattended. Aside from the timer based step downs, the light is very well regulated at each brightness level.

There seem to be some discrepancies between advertised and actual output in low, and runtimes for medium and low. Thorfire need to update this.

In comparison with other lights, the claimed lux output of 11,200cd appears to be accurate.

The emitter is neutral white, which I much prefer over the more commonly found cool white emitters. The CCT appears to be between 4500 and 5000k. However, due to the “technology” found in newer Cree emitters such as the XP-L2 and XP-G3, there is considerable tint shift between the warmer yellow hotspot and cooler (slightly purple) spill beam. The tint shift may be a reason why Thorfire did not choose a cool white tint. Whilst this tint shift may be an issue for “white wall hunters”, in real world use it is much less of an issue (as per the outdoor beamshot) . CRI appears to be well above 70CRI – I’d like to see an accurate evaluation of the CRI for this light, as colour rendition was surprisingly good.

Due to XP-L2 emitter, smooth reflector, and small head, the beam is well balanced between flood and throw. The spill beam is much narrower and more intense than a Convoy S2+ with XM-L2/OP reflector 18650 tube light, and almost as narrow and just as intense as a Convoy S2+ with XP-L HI/SMO reflector.

The comparison beam shots below have Convoy S2+ Desert Tan on left, and Thorfire TK15S on right (note: neither lights are on high, so this is for beam profile comparison only).

PWM could not be detected on video, or during long exposure photos in any mode. So the light is either constant current, or the PWM is very fast.

Outdoor beam shot – high mode, f5.6, 4sec, ISO400

Two light painting photos using Thorfire TK15S (note: purple starburst from Ledlenser P7.2!)

Conclusion

Things I liked:
Good build quality
Momentary functionality can work with any memorised mode
Unique up and down mode order
Flashy modes out of normal mode cycle (requred double click or long press to activate).
Good initial output and lux for a 18650 tube light
Step down not excessively fast (3 mins)
Moonlight mode
Accepts wide range of protected and unprotected 18650 batteries (protected Sanyo/Panasonic GA’s recommended).
Neutral white emitter as standard
Smooth bezel

Things I didn’t like:
No USB charging or battery check functionality (I’m being very picky at this price point)
Significant tint shift due to newer Cree LED technology
Lack of accessories and tint options
Errors in manual and output/runtime specifications

The Thorfire TK15S is fantastic budget tube light. It stands out from the budget crowd with a unique user interface with up-down-up-down mode order, and momentary bursts of light possible in all modes. The neutral white emitter also stands out from the usual cool white fare. The 3 minute step down from high makes this light suitable for non-flashlight experts. Due to the useful momentary function, the Thorfire TK15S will definitely be staying in my camera bag when I’m out taking night photography!

Note: The reviewed Thorfire TK15S is different to the TK15 (no “S”) which does not have the tail switch and momentary functionality.

Edited by: stephenk on 09/07/2017 - 07:32
kennybobby
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Thank you for pulling back the covers of this light—you did a great job and i enjoyed reading the review, bonus points for the light painting and xrays…

firedome
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Nice review, thanks! Thumbs Up

“We can easily forgive a child who is afraid of the dark; the real tragedy of life is when men are afraid of the light.

-Plato

stephenk
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kennybobby wrote:
Thank you for pulling back the covers of this light—you did a great job and i enjoyed reading the review, bonus points for the light painting and xrays…

firedome wrote:
Nice review, thanks! Thumbs Up

Thanks! With lots of the reviews of the same lights at the moment, it is nice to get appreciation. Makes the time invested in the review worthwhile. Smile
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Nice review. It does have a battery check of sorts. Low voltage warning. If I remember right, at 3v it starts to flash where one click turns the light back on to normal. At 2.8v, it flashes then shuts off. One click turns it back on. Problem is, none of this is mentioned in the manual.

stephenk
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RobertB wrote:
Nice review. It does have a battery check of sorts. Low voltage warning. If I remember right, at 3v it starts to flash where one click turns the light back on to normal. At 2.8v, it flashes then shuts off. One click turns it back on. Problem is, none of this is mentioned in the manual.
Thanks for that info. Thorfire need to have that in the manual. I wasn’t game to risk an unprotected battery finding out!
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stephenk wrote:
RobertB wrote:
Nice review. It does have a battery check of sorts. Low voltage warning. If I remember right, at 3v it starts to flash where one click turns the light back on to normal. At 2.8v, it flashes then shuts off. One click turns it back on. Problem is, none of this is mentioned in the manual.
Thanks for that info. Thorfire need to have that in the manual. I wasn’t game to risk an unprotected battery finding out!

I only found out about it looking at the Sofirn SP31 manual. It has the exact same driver as the TK15S. Then tested it, and sure enough, it had the same low voltage warnings at the exact same voltages. But yes, TF needs to add this to the manual. Someone not familiar with flashlights would think something is wrong with the light

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Thanks for the review!


You came to a fairy tale Big Smile

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Quote:
The comparison beam shots below have Convoy S2+ Desert Tan on left, and Thorfire TK15S on right (note: neither lights are on high, so this is for beam profile comparison only).

Is the S2+ tint 1A in your comparison shots?

stephenk
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Yes the left is 1A on the XP-L HI S2+ which is slightly warmer than the 1A on my XM-L2 S2+. Edit: I think the TK15S is 3D but it is difficult to assess due to the tint shift (which I’ll note is really a non issue outdoors).

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Forget buying the light…sell me the camera!

never fear shadows…it means a light shines nearby

stephenk
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The light painting photos and outdoor beam shot are taken with an entry level DSLR – Nikon D3300.
The rest of the review photos are using the iPhone 6, and a medical x-ray unit.

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Stephen, how did you take that X-ray? lol. My assumption is that you wouldn’t be able to see anything since the body is all metal.

My gratitude to those who are willing and able to help others (in whatever way you can)! Being human is more than just existing for yourself. Smile

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eebowler wrote:
Stephen, how did you take that X-ray? lol. My assumption is that you wouldn’t be able to see anything since the body is all metal.

Xrays go through aluminum easy. Aluminum is used as filters and calibrating xray machines. Xrays can go through just about anything depending on how thick and what type of material. It might take 2 ft thick piece of aluminum to block as much as .25mm of lead would. Depending where the machine is located, concrete block walls that face the interior of the building are required to be two feet thick, or have a lead wallboard layer. Many times a chest xray panel is bolted to the wall, so the machine is pointing right at it from approx 70 inches away.

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Kick Ass!  What an awesome review.  Great info and that x-ray tells me more about the light than a ton of tear down pics ever could.   Kind of wondering why the tail cap was not fully screwed on, but that is just me being curious.

As usual, my wife and I really dig your light paintings.  Rock on stephenk!

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How long was the exposure time in those two light painting shots? Nicely done, by the way!

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Thanks Rob! I had no idea! Smile

My gratitude to those who are willing and able to help others (in whatever way you can)! Being human is more than just existing for yourself. Smile

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Pete7874 wrote:
How long was the exposure time in those two light painting shots? Nicely done, by the way!

The first one was around 30secs, the second one was around 90secs. Wanted a bit more symmetry for the latter – a slope probably wasn’t the best site, but I wanted the street lighting on the trees.
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Thanks for the review. I see $17.39 with the coupon code in the OP.

stephenk
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Gj wrote:
Thanks for the review. I see $17.39 with the coupon code in the OP.

Maybe contact the Banggood rep on this forum, though I think prices tend to fluctuate all the time.