Tag Archives: 3.5 stars

Wurkkos WK15

The WK15 is a relatively compact, inexpensive, general-purpose flashlight running on a single 21700 battery. It features the common Cree XHP50.2 emitter.

  1. Introduction
  2. Manufacturer Specifications
  3. Package Details
  4. Build
  5. User Interface
  6. Circuit Measures
  7. Emitter Measures
  8. Beamshots
  9. Testing Results
  10. Runtimes
  11. Pros and Cons
  12. Overall Rating
  13. Preliminary Conclusions
  14. Acknowledgement

Introduction

I am still working through my backlog of lights – this WK15 sample was received late last summer.

I’ve reviewed a number of general purpose 1×21700 lights by Wurkkos and Sofirn, and have typically been very impressed with the performance and build for the price. I noticed a general lack of reviews on the WK15, which seems to be a particularly inexpensive model in this space. Wurkkos agreed to send me a sample to review.

Equipped with the popular XHP50.2 emitter, available in both the neutral white 5000K and cool white 6000K colour temperatures (I opted for 5000K). The WK15 rated specs are very similar to many competing models in this space, despite its relatively compact size. Let’s see how it performs in my testing.

Manufacturer Specifications

Note: As always, these are simply what the manufacturer provides – scroll down to see my actual runtimes.

FeatureSpecs
MakerWurkkos
ModelWK15
EmitterXHP50.2
Tint5000 K
Max Output (Lumens)3,000
Min Output (Lumens)1
Max Runtime500 hours
Max Beam Intensity (cd)11,892 cd
Max Beam Distance (m)218 m
Constant Levels6
FlashingStrobe
Battery1x21700
Weight (w/o battery)-
Weight (with battery)70 g
Length113 mm
Head Diameter27.8 mm
Body Diameter-
WaterproofIP68

Package Details




Unlike the modern style packaging of the newer higher-end models from Sofirn and Wurkkos, the WK15 comes in fairly basic packaging. Inside I found:

  • Wurkkos WK15 flashlight
  • Wurkkos-branded 5000mAh 21700 battery
  • Wrist lanyard
  • USB-C charging cable
  • 2 Spare O-rings
  • Manual

It’s a decent package for a “budget” build, but I would like to see a holster included. FYI, Wurkkos sells an inexpensive holster (small size for ~$2 USD) that fits this light.

Build


From left to right: LiitoKala 21700 (5000mAh), Vapcell 21700 F56 (5600mAh), Emisar D4K, Imalent MS03, Convoy S21E, Skilhunt M300, Wurkkos WK15, Wurkkos TS22, Sofirn SP35T, Cyansky P25, Nitecore P20iX, Acebeam E70.








The WK15 is a very compact 1×21700 light – its definitely on the smaller side of the lights I’ve tested in this class. It vaguely reminds me of the Fenix E35, although in a more basic build.

The tailcap is flat, with a lanyard cut-out area. It is able to tailstand stably. Tailcap threads are square-cut and anodized, with good feel. Thanks to the anodized tailcap threads, you can easily lock-out this light by a simple twist of the tailcap.

The electronic switch on the side of the head has red and green LEDs underneath to show charge status. Feel and traverse of the electronic switch is very similar to a lot of Wurkkos and Sofirn lights – it’s ok, but could be a bit tighter/firmer (i.e., hard switch covers always have some degree of play).

The light’s USB-C charging port is located on the opposite side from the switch, under a rubber cover. The cover fits pretty well – not too too tight, not too loose. I expected waterproofness is reasonable (i.e., more splashable than watertight).

There is a lot of traditional knurling on the light – not super aggressive, but more than most, producing excellent grip. Anodizing looks to be good quality for type II, with no damage on my sample. I would describe the finish as matte. Thanks to included bi-directional clip, the light will not roll on its side. The clip attaches firmly, and is good for both bezel up and down carry.

Inside, the light comes with a Wurkkos-branded standard-sized 5000mAh 21700 battery, with a slightly raised flat-top.

This is a solid little light, with good grip and handfeel. It does seem a bit more budget than the rest of the Wurrkos or Sofirn line – but that is in keeping with its lower price point.


The WK15 comes with a XHP50.2 HD emitter, in neutral or cool white tint (neutral on my sample). The reflector is fairly shallow and well textured (moderate orange peel, MOP). There doesn’t seem to be any kind of anti-reflective coating on the lens.

As expected, there is noticeable tint/colour shifting across the periphery of the beam, with a warmer yellowish white hotspot surrounded by a coolish spill and purplish shift near the edge of the periphery. This is a well-known issue with HD emitters of the XHP family, particularly obvious on the XHP50.2. The textured reflector normally helps to even it out, but I do find my sample is rather noticeable.

The bezel is flat black aluminum. So you can headstand stably, but you can’t tell if the light is on in that orientation.

User Interface

The WK15 has a straightforward user interface, and one that is similar to many basic Sofirn and Wurkkos lights.

Mode levels: Moonlight, Eco, Low, Mid, High, Turbo, and Strobe

From OFF:

  • Press-and-hold: Turns on in Moonlight mode.
  • Single-click: Turns On in last memorized mode (only Eco, Lo, Med and Hi can be memorized).
  • Double-click: Turns On in Turbo.
  • Triple-click: Turns On in Strobe.
  • 4 clicks: Activate Lock-out mode. Four clicks to unlock.

From ON:

  • Press-and-hold: Cycle between Eco > Lo > Med > Hi (in sequence).
  • Single-click: Turns Off.
  • Double-click: Jumps to Turbo. Single click jumps you back to last memorized mode.
  • Triple-click: Jumps to Strobe.Single click jumps you back to last memorized mode.

Mode memory:

Yes, for non-Moonlight, non-Turbo constant output modes.

Shortcuts:

  • Moonlight mode: Press-and-hold the switch from Off.
  • Turbo mode: Double-click the switch from On or Off.
  • Strobe: Triple-click the switch from On or Off.

Low voltage warning:

Not that I noticed.

Lockout mode:

Yes, you can physically lock out the light at the tailcap. There is an electronic lockout as well that you can trigger manually (i.e., no auto-lockout).

Battery indicator:

Not that I noticed.

Reviewer Comments:

A very serviceable and standard interface – easy to remember and use.

Circuit Measures

No Pulse-Width Modulation (PWM):

Moonlight:
Moonlight

Eco:
Eco

Low:
Lo

Med:
Med

High:
Hi

Turbo:
Turbo

There is high frequency circuit noise on all levels above Moonlight. This is common on a lot of inexpensive lights, and is not necessarily a concern as it is not visually detectable. I measured the frequency as just over 21 kHz on all modes from Eco through Turbo (note the last trace above shows an inaccurate lower value – the auto measure feature in the oscilloscope software sometimes gets fooled by slower harmonics).

Strobe:

Strobe is a constant 14 Hz.

Charging:

The switch button shows solid red when the light is charging. Changes to solid green when the charging is complete.

Resting voltage <3.0V

Resting voltage >3.0V

The WK15 has a two-stage charging feature, as seen on many good quality modern lights (i.e., where there is a lower initial charging rate when the cell is heavily discharged). I’m actually surprised to see it here, given the budget price. This is also a very high charging rate for the class, and will charge a 21700 cell quickly.

Standby / Parasitic Drain:

Yes, due to the electronic switch. I measured it at 1.7 mA, which is moderately high. For a 5000mAh cell, that would mean you would deplete the battery is about 4 months. But you can easily cut this current by a simple twist of the tailcap.

Emitter Measures

In this section, I directly measure key emitter characteristics in terms of colour temperature, tint, and colour rendition. Please see my Emitter Measures page to learn more about what these terms mean, and how I am measuring them. As tint in particular can shift across levels, I typically stick with the highest stably regulated level for all my reported measures.

As explained on that page, since I am using an inexpensive uncalibrated device, you can only make relative comparisons across my reviews (i.e., don’t take these numbers as absolutely accurate values, but as relatively consistent across lights in my testing).

WK15 on Hi:

The key measures above are the colour temperature of ~4800K, and a slight positive tint shift (+0.0103 Duv) to slight greenish-yellow at this temperature. I wasn’t able to get a reliable CRI (Ra) measure.

These values are consistent with the performance of a neutral white XHP50.2 emitter, and match my visual experience of this light. Note that there is a noticeable tint shift from yellowish hotspot to cooler white spill with purplish spillbeam edge, which is common to 50.2 HD emitters.

Beamshots

All outdoor beamshots are taken on my Canon PowerShot S5 IS at f/2.7, 0.5 secs exposure, ISO 400, daylight white balance. The bend in the road is approximately 40 meters (~45 yards) from the camera. Learn more about my outdoor beamshots here (scroll down for the floody light position used in this review).

Click on any thumbnail image below to open a full size image in a new window. You can then easily compare beams by switching between tabs.



As you can see above, the WK15 has a pretty traditional beam for this class.

Testing Results

My summary tables are generally reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. In addition to the links above, please see my output measures page for more background.

All my output numbers are based on my home-made lightbox setup. As explained on that methodology page, I have devised a method for converting my lightbox relative output values to estimated lumens. Note that my lightbox calibration runs higher than most hobbyists today, but I’ve kept it to remain consistent with my earlier reviews (when the base calibration standard was first established). On average though, I find my lumen estimates are ~20% higher than most other modern reviewers.

My Peak Intensity/Beam Distance are directly measured with a NIST-certified Extech EA31 lightmeter.

WK15 Testing Results

ModeSpec LumensEstimated Lumens @0secEstimated Lumens @30 secsBeam Intensity @0secBeam Intensity @30secsBeam Distance @30secsPWM/Strobe FreqNoise FreqCharging Current <3VCharging Current >3VParasitic DrainWeight w/o BatteryWeight with BatteryCCT (K)DuvCRI
Moon11.21.2---No21.25 kHz0.17 A2.15 A1.70 mA71 g140 g---
Eco101010---No21.25 kHz0.17 A2.15 A1.70 mA71 g140 g---
Low100150150---No21.25 kHz0.17 A2.15 A1.70 mA71 g140 g---
Med550590585---No21.25 kHz0.17 A2.15 A1.70 mA71 g140 g4,8150.0113-
High1,5001,5501,550---No21.25 kHz0.17 A2.15 A1.70 mA71 g140 g---
Turbo3,0003,5003,30013,500 cd12,100 cd220 mNo1.24 kHz0.17 A2.15 A1.70 mA71 g140 g---
Strobe3,000-----14.2 Hz21.25 kHz0.17 A2.15 A1.70 mA71 g140 g---

My WK15 sample very closely matches the reported specs for this light. I know my lightbox’s relative calibration is generously high for modern high-output lights, however.

That said, my NIST-calibrated luxmeter is accurately calibrated to an absolute standard, and similarly reports very consistent peak intensity throw to reported specs.

To view and download full testing results for all modern lights in my testing, check out my Database page.

Runtimes

As always, my runtimes are done under a small cooling fan, for safety and consistency. To learn more about how to interpret runtime graphs, see my runtimes methodology page. Note that on average, my lightbox’s calibration seems to be ~20% higher than most modern reviewers.

Med

Hi

Max

Consistent with the budget price, it looks like the WK15 is using a simple linear FET driver. Performance is extremely consistent with the Sofirn SP35T – basically, a direct-drive-like pattern where the battery resistance is ultimately regulating output over time. Sadly, there is no flat voltage-regulated performance here, unlike the higher-end TS22 for example.

All that said, performance is not bad – it is just very basic. Note however that both the Hi mode as well as the Turbo mode step down rather quickly, compared to some other lights. But the flip-side of that is the light certainly lasts for a reasonably long amount of time.

Pros and Cons

ProsCons
The light has a solid build, with an electronic switch.Circuit is not voltage-regulated, producing a slowly decreasing output instead of flat runtimes.
The light has a serviceable basic user interface, easy to remember and use.The circuit is also noticeably less efficient than other current-controlled lights with flat regulation.
Price is reasonably low.XHP50.2 HD emitters produce well known tint shifts across the beam, with a yellowish hotspot, cool white spill, and purplish spillbeam edge.

Overall Rating

Preliminary Conclusions

The WK15 is a compact but solid light, with a decent physical build and good (if basic) user interface. You could do a lot worse for the price!

But as described above, the circuit performance is disappointing here. Similar to the Sofirn SP35T, you get a reasonable amount of light for a reasonable amount of time. But its performance just doesn’t compare to the fully-regulated competition, such as the efficient (but more expensive) TS22 in comparison. That said, the published output specs seem pretty accurate for this model, with a good range of output levels.

The XHP50.2 HD emitter is known for a lot of tint/chromatic variation across its beam, and this example is no different. I can’t specifically fault this model in that regard, but my WK15 sample is particularly noticeable.

Taken together, I find these drawbacks limit this light to a maximum 3.5 star rating on my subjective scale. This is still quite decent, and better than some equivalent models at this price point. But there are couple of others I might recommend over this. That said if you like a straightforward interface and grippy finish, this light does fit the bill for the budget class.

Acknowledgement

The WK15 was supplied by Wurkkos for review. As always, all opinions are my own and the light received the same rigourous and objective testing as all other lights that I have reviewed. At the time of review, this light retails for ~$25 USD (~$35 CDN) with battery included on the Wurkkos website here.

Wurkkos TD01

The TD01 is a budget tactical flashlight featuring a TIR lens for maximum throw with minimal spill. Powered by a single included 21700 battery, with both tactical and general user interface options.

  1. Introduction
  2. Manufacturer Specifications
  3. Package Details
  4. Build
  5. User Interface
  6. Circuit Measures
  7. Emitter Measures
  8. Beamshots
  9. Testing Results
  10. Runtimes
  11. Pros and Cons
  12. Overall Rating
  13. Preliminary Conclusions
  14. Acknowledgement

Introduction

The TD01 is a new tactical/hunting-style flashlight from Wurrkos. Featuring the low-profile Luminus SFT40 coupled with a large focused TIR, this 1×21700 flashlight is clearly designed to be a dedicated thrower. I was certainly impressed with the compact TS22 from Wurkkos, so am happy review this larger thower model.

Physically, the light is still fairly compact for having such a large head. There is also a tailcap forward clicky switch, coupled with an electronic side switch in the head. This design is very reminiscent of the reflectored Sofirn C8L – a comparison which, as we will see, runs more than skin deep.

Let’s see how it compares in my testing.

Manufacturer Specifications

Note: as always, these are simply what the manufacturer provides – scroll down to see my actual runtimes.

FeatureSpecs
MakerWurkkos
ModelTD01
EmitterSFT40
Tint6000 - 6500 K
Max Output (Lumens)2,200
Min Output (Lumens)30
Max Runtime70 hours
Max Beam Intensity (cd)270,000 cd
Max Beam Distance (m)1039 m
Constant Levels5
FlashingStrobe, SOS, Beacon
Battery1x21700
Weight (w/o battery)
Weight (with battery)200 g
Length152 mm
Head Diameter59 mm
Body Diameter-
WaterproofIPX-8

Package Details





I really like the packaging of the higher-end lights from Wurkkos (and Sofirn, which share a common manufacturing plant). The hard-sided box comes with a lot of printed specs on the sleeve, and a clear separation of items and components inside thanks to the cut-out foam. Inside the box, I found:

  • Wurkkos TD01 flashlight
  • Wurkkos-branded 5000mAh 21700 battery
  • Wrist lanyard
  • USB-C charging cable
  • 2 Spare O-rings
  • Manual

It’s a decent package for a “budget” build, but I would really like to see a holster included. These form factor lights tend not to fit well into after-market holsters.

Build


From left to right: LiitoKala 21700 (5000mAh), Acebeam 21700 USB-C (5100mAh), Lumintop D3, Convoy M21F, Sofirn C8L, Wurkkos TS30S Pro, Wurkkos TD01, Acebeam L19 V2.0, Acebeam P17.










The Wurkkos TD01 immediately reminds me a lot of the Sofirn C8L in its overall build and feel. This is not surprising, since these lights come off the same manufacturing production line. I will get into the specifics below, but it is a solid build overall, with good handfeel. I would rate it as above average quality for a budget light, but lacking some of the nicer touches of a true top-of-the-line light. And while substantial in overall dimensions and weight, it is still pocket-able to some degree (i.e., with the head protruding out).

Like the C8L, there is a physical forward clicky switch in the tailcap, used for the turning the light on/off. However, switch feel is not as good on this particular sample – I find it too “soft and squishy” (i.e., you need to press more than expected to activate in momentary mode, and it’s too easy to then accidentally click). This makes momentary or a double-press (required to jump to Turbo from Off) tricky to do consistently. See the user interface section below for more information.

There are two raised tailcap guards that can serve as the lanyard attachment point. However, unlike the C8L (which had exact same arrangement), my TD01 is not able to tailstand at all – the tactical switch protrudes too far, beyond the switch guard rails. This is a missed opportunity on this model (or at least, this sample).

Tailcap threads are square-cut and anodized, with good feel. I always recommend you keep a light stored locked out when not in use. Thanks to the anodized tailcap threads, you can do this easily on the TD01 by a simple twist of the tailcap.

There is a raised side-mounted electronic switch on the side of the head, with red and green LEDs underneath to show charge status. Feel and traverse of the electronic switch is very similar to a lot of Wurkkos and Sofirn lights – it’s ok, but could be a bit tighter/firmer (i.e., hard switch covers always have some degree of play).

The side switch shines a bright red when charging the battery through the light’s USB-C charging port (green when fully charged). The port is located on the opposite side from the switch, under a rubber cover. The cover fits pretty well on the TD01 (just like the C8L) – not too too tight, not too loose. I expected waterproofness is reasonable.

There is no actual knurling on the light, but large raised concentric rings around the body tube help with grip (pattern is virtually identical to the Wurkkos TS22). When combined with the head and tailcap ridge detail, I would say overall grip is pretty good. Note that the light can roll away completely unfettered when on its side – the head has a completely smooth round edge, and lacks any cut-outs of any kind (even the C8L had some gentle ones, to help reduce roll a little). I recommend you stand it upright on its head when not in use. Anodizing looks to be good quality for type II, with no damage on my sample. I would describe the finish as satin.

Inside, the light comes with a Wurkkos-branded standard-sized 5000mAh 21700 battery, with a slightly raised flat-top. There is a good size spring in the head, ensuring good contact (always a good idea for a “tactical” light).

As with all things, it comes down to your expectations. The TD01’s build is a very good approximation of a quality tactical light, but it does have a number of small issues and inconsistencies that add up (and reflect its budget status).






The TD01 uses a very distinctive large TIR optic looks a lot like the Acebeam L19, except with a thicker centre “column.” I’ve taken pics from a lot of angles above, so you can see how it generally obscures the emitter (except in the second shot above). The low-profile SFT40 is ideal for producing a very focused beam, which the TD01 does very well.

The bezel is crenelated black aluminum – not too aggressive, so you can headstand stably. Note that some of the promotional material seems to suggest the light has a stainless steel strike bezel – it doesn’t, just this low profile aluminum bezel (again, in keeping with its budget nature). There doesn’t seem to be any kind of anti-reflective coating on the lens.

Here are a couple of white wall beamshots, to give you an idea of how focused it is:


I’ve included the white wall beamshots above to highlight a single bright ring that is visible in the mid-distance around the hotspot. Note that in real life the hotpot is much smaller than it appears above (the camera settings are over-saturating the hotspot intensity). But I’ve chosen these settings to better show you the ring. Rest assured, the ring is not that distracting in real life, but it is present (scroll down for outdoor beamshots).

User Interface

The TD01 has a user interface that is identical to the Sofirn C8L, again reflecting their shared heritage. Like many “tactical” lights, you have two sets of possible modes; Mode Group 1 for General use, and Mode Group 2 for Tactical use.

To switch between groups, press-and-hold the side switch for >3 secs when On.

Mode Group 1 (default) available levels: Eco, Low, Medium, High, Turbo, Strobe, SOS, and Beacon.

Mode Group 1, from OFF:

  • Tail switch, partial-press: Momentary On in last memorized mode.
  • Tail switch, single-click: Turns On in last memorized mode.
  • Tail switch, double-press: Turns On in last memorized mode and then jumps to Turbo (click to stay locked-on in Turbo). You have be very rapid on the double-press to jump to Turbo.
  • Side switch, press-and-hold: Nothing – but if you click the tail switch while holding down the side switch, the light will activate in Eco mode.
  • Side switch, single-click: Nothing.

Mode Group 1, from ON:

  • Tail switch, partial-press: Nothing.
  • Tail switch, single-click: Turns Off.
  • Side switch, press-and-hold (3 secs): Switch to Mode Group 2 (see below)
  • Side switch, single-click: Steps up to the next non-Turbo constant output mode (in sequence, Eco > Lo > Med > High).
  • Side switch, double-click: Turbo.
  • Side switch, triple-click: Strobe.
    • Side switch, double-click when in Strobe: Cycle through in sequence Strobe > SOS > Beacon (with no mode memory).

Mode 1, Mode memory:

Yes, for non-Turbo constant output modes.

Mode 1 Shortcuts:

  • Eco mode: Press and hold the side switch while turning on at the tail switch.
  • Turbo mode: Double-click the side switch from On, or double-press the tail switch from Off.

Mode 2 available levels: Medium, Turbo, and Strobe.

Mode 2 functions basically as a stripped-down “tactical” version of Mode 1. The main differences are:

  • Single-click of the side switch from On only selects between Medium and Turbo now.
  • Double-click of the the tail or side switch goes to Strobe instead of Turbo.
  • There is no level memory now.

Otherwise, the two modes function the same way.

Battery indicator:

When first activating the light, the indicator on the side switch shows the battery voltage  (lasts for ~5 secs):

  • Solid green: ~70-100%
  • Flashing green: ~40-70%
  • Solid red: ~10-40%
  • Flashing red: 0-10%

Mode memory:

Yes, in the Mode Group 1 for non-Turbo constant output modes. There is no memory in the Mode Group 2.

Shortcuts:

  • Mode Group 1: Yes, for Eco, Turbo and Strobe (see above).
  • Mode Group 2: Yes, for Eco and Strobe (see above).

Low voltage warning:

Yes, the main light will step down as the battery is running low. It will then turn Off at ~2.95V

Lock-out mode:

Yes, but physically – you lock-out the light by a twist of the tailcap.

Reviewer Comments:

As with the build, I think this is a reasonable dual-mode UI for a tactical light, with a general mode set and a tactical mode set.

One thing I’m not crazy about is the multiple-press functionality of the tactical tailcap switch. I didn’t really find this as much of an issue on the C8L, but my TD01’s switch is noticeably softer. This made it harder to consistently double-click the tailcap (i.e., soft-press, then press-and-click rapidly). But in any case, this level switching feature at the tailcap is completely unnecessary on the C8L/TD01 anyway, as you always have the electronic side switch in the head to control output levels (including accessing Turbo).

On the whole, I personally prefer General Mode Group 1, for its versatility. I suppose “tactical” people will like the lack of mode memory in Tactical Mode Group 2.

Circuit Measures

Pulse-Width Modulation (PWM):

Eco:
Eco

Low:
Lo

Mid:
Mid

High:
Hi

Turbo:
Turbo

There is high frequency circuit noise on all levels except Turbo on the TD01, at a visually undetectable constant frequency of 19.9 kHz. This is different from the C8L, which was completely noise free. As is often the case, this constant circuit noise increases in amplitude with output level. It is definitely not PWM, although it has a bimodal distribution (i.e., there is a secondary harmonic of rising/cresting waves at ~5 kHz), as shown in the expanded view of the High mode below

Turbo

Again, this is not a problem per se, as you won’t be able to see any of the above in use. But from long experience, I find this doesn’t bode well when it comes to overall circuit regulation and efficiency (scroll down for runtimes).

Strobes:

Strobe:


Strobe alternates between 8 Hz and 14 Hz every 2 secs or so. Very distracting.

SOS:

A standard SOS mode, relatively slow.

Beacon:

A single flash beacon once every 2 secs (0.5 Hz).

Charging:

The switch button shows solid red when the light is charging. Changes to solid green when the charging is complete.

Resting voltage <3.0V

Resting voltage >3.0V

The TD01 has a two-stage charging feature, as seen on many modern lights (although oddly, not its sister light the C8L) where there is a lower initial charging rate when the cell is heavily discharged. The initial charging rate is ~0.25A, which jumps to ~1.55A once the cell exceeds 3.0V resting. These rates are good for a 21700 cell. Charging terminated at ~4.19V on my sample. This is probably the first example where the TD01 has a slight advantage over the C8L.

Standby / Parasitic Drain:

None. That is one of the nice things about a physical clicky switch, no standby current. 🙂 And you can always lock-out the light by a twist of the tailcap, to prevent accidental activation.

Emitter Measures

In this section, I directly measure key emitter characteristics in terms of colour temperature, tint, and colour rendition. Please see my Emitter Measures page to learn more about what these terms mean, and how I am measuring them. As tint in particular can shift across levels, I typically stick with the highest stably regulated level for all my reported measures.

As explained on that page, since I am using an inexpensive uncalibrated device, you can only make relative comparisons across my reviews (i.e., don’t take these numbers as absolutely accurate values, but as relatively consistent across lights in my testing).

TD01 on Med:

The key measures above are the colour temperature of ~6045K, and a noticeably positive tint shift (+0.0138 Duv) to greenish-yellow at this temperature. For CRI (Ra), I measured a combined score of 64.

These values are very consistent with the rated specs for the cool white SFT40 emitter on my sample, and match my visual experience of this light.

Beamshots

All long-distance outdoor beamshots are taken on my Canon PowerShot S5 IS at f/2.7, 1 sec exposure, ISO 400, daylight white balance. The tree at the centre of the hotspot is approximately 90 meters (~100 yards) from the camera. Note the road dips down and turns away in the distance, out of the camera’s sight line. Learn more about my outdoor beamshot locations here.

Click on any thumbnail image below to open a full size image in a new window. You can then easily compare the overall beams by switching between tabs.



To help illustrate the hotspots better, I’ve also cropped the raw pictures around the centre of the frame. As before, click on any thumbnail below to open a full size image in a new window.



As you can see above, the TD01 is a very focused thrower. It does put out a little more light into the periphery than the L19, and with a slightly larger hotspot. But this is an incredible thrower.

Testing Results

My summary tables are generally reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. In addition to the links above, please see my output measures page for more background.

All my output numbers are based on my home-made lightbox setup. As explained on that methodology page, I have devised a method for converting my lightbox relative output values to estimated lumens. Note that my lightbox calibration seems to run higher than most hobbyists today, but I’ve kept it to remain consistent with my earlier reviews (when the calibration standard was first established).

My Peak Intensity/Beam Distance are directly measured with a NIST-certified Extech EA31 lightmeter.

TD01 Testing Results

ModeSpec LumensEstimated Lumens @0secEstimated Lumens @30 secsBeam Intensity @0secBeam Intensity @30secsBeam Distance @30secsPWM/Strobe FreqNoise FreqCharging Current <3VCharging Current >3VParasitic DrainWeight w/o BatteryWeight with BatteryCCT (K)DuvCRI
Eco302928---No19.858 Hz0.25 A1.55 ANo193 g261 g---
Low150155150---No19.858 Hz0.25 A1.55 ANo193 g261 g---
Med350290285---No19.864 Hz0.25 A1.55 ANo193 g261 g6,0450.013864
High900760740---No19.878 Hz0.25 A1.55 ANo193 g261 g---
Turbo2,2002,1002,000255,000 cd235,000 cd970 mNo-0.25 A1.55 ANo193 g261 g---
Strobe2,200-----8-14 Hz-0.25 A1.55 ANo193 g261 g---
SOS350------19.858 Hz0.25 A1.55 ANo193 g261 g---
Beacon2,200-----0.5 Hz-0.25 A1.55 ANo193 g261 g---

Unlike my TS22 and C8L samples, the TD01 has inflated specs on its higher levels, compared to what I measure in my lightbox. Oddly, it’s worse on the Med and Hi levels, with Turbo only being inflated by ~10% in my lightbox. Although it is probably even worse than the numbers above suggest, as I know my lightbox’s relative calibration is generously high for modern high-output lights.

My NIST-calibrated luxmeter is accurately calibrated to an absolute standard, and reports slightly lower beam intensity on Turbo (comparable to my lightbox for overall output measures). But this is still an impressive showing.

To view and download full testing results for all modern lights in my testing, check out my Database page.

Runtimes

As always, my runtimes are done under a small cooling fan, for safety and consistency. To learn more about how to interpret runtime graphs, see my runtimes methodology page.

Max

Hi

Med

One thing these results make very clear: Wurkkos is definitely not using a buck driver on the TD01. There had been some apparent miscommunication on this point when the light was first announced. It appears to be using a standard FET driver, producing the non-voltage-regulated runtimes you see above.

In and of itself, this is not necessarily a problem – such lights can still be relatively efficient. But that doesn’t really seem to be the case here. It is not as efficient as the Convoy S21E that I tested with this same SFT40 emitter – that light had perfectly flat regulated output (which lowers overall efficiency, since it spends a lot more time at higher output, plus has circuit overhead to consider). So performance here is disappointing, especially in comparison to the outstanding efficiency and regulation that you can see on the TS22 and the Sofirn C8L.

You can also see that the TD01 steps down very quickly on Turbo and Hi. To better show this initial step-down pattern, here is a expanded view of first few minutes of those runtimes:

Max-extended

Pros and Cons

ProsCons
As advertised, the light is a very dedicated thrower, thanks to its large focused TIR optic.Circuit is not voltage-regulated, producing a slowly decreasing output instead of flat runtimes. It also appears to be less efficient then other current-controlled lights with flat regulation.
The light has a solid build with good handfeel, although there are some small issues (see Cons).Tactical forward clicky switch has a softer feel than typical, making signalling or double-clicking difficult. It also protrudes too far, preventing tailstanding.
Price is incredibly low, making this arguably the best throwing light of the 1x21700 class at this price point.Light can roll very easily, with no preventive measures to impeed.
Output specs seem to be somewhat inflated.
Would really benefit from an included holster.

Overall Rating

Preliminary Conclusions

Many of my build observations of the Sofirn C8L are true here as well – in many ways, this is a sister light to that model, but one that is heavily focused for throw. The lights are very similar in overall build quality and packaging, reflecting the common factory they are produced at (despite being different companies). The dual physical tailcap clicky and side electronic switch design – along with an identical user interface – further cements their close relationship.

But the switches are where I find the comparison starts to break, and not in the TD01’s favour. The switch feel is softer on my TD01 sample than the C8L, limiting its value for momentary signalling. And because it protrudes further than my C8L sample, the TD01 doesn’t tailstand at all, which is disappointing. Not a huge deal of course, but it is a minor annoyance that could easily have been avoided.

Overall output/runtime efficiency is fine for a SFT40 emitter, but overall output is lower than rated for the specs on this model. And unfortunately regulation is disappointing here too – especially against the outstanding TS22 and Sofirn C8L. It looks like Wurkkos simply reused an older driver/circuit for the SFT40 emitter, and updated it with the C8L’s user interface. I would have preferred to see a fully voltage-regulated pattern here.

Beam pattern is very throwy as advertised, and I find the TIR optic does a really good job of focusing almost exclusively for throw. There is just one noticeable beam ring – but that’s more an issue on a white wall than in actual use outdoors. It really is quite the spotlight!

Despite the close similarities to the C8L – and the impressive TIR optic here – I can’t give this light higher than 3.5 stars in its current form. The physical quirks with the switch, and the more significant circuit issues (i.e., off from the specs, lower sustained output, lack of voltage regulation, reduced efficiency, circuit noise, etc.) knock this light down a full star from the C8L in my view.

It is still an incredible value for the price, and I appreciate all that it does bring to the table. If the issues above don’t matter to you, this is a great way to experience massive TIR throw at a budget price (it really is unbelievably cheap!). As the beamshots show, that is an incredible beam. With a little more fine-tuning, this could become a top pick in the dedicated TIR thrower class.

Acknowledgement

The TD01 was supplied by Wurkkos for review. As always, all opinions are my own and the light received the same rigourous and objective testing as all other lights that I have reviewed. At the time of review, this light retails for ~$45 USD (~$60 CDN) with typical discounts on their website here.

Sofirn IF25A

The IF25A is a popular compact every-day-carry light, running on an included single 21700 battery. It also features the sophisticated Anduril user interface.

  1. Introduction
  2. Manufacturer Specifications
  3. Package Details
  4. Build
  5. User Interface
  6. Circuit Measures
  7. Emitter Measures
  8. Beamshots
  9. Testing Results
  10. Runtimes
  11. Pros and Cons
  12. Overall Rating
  13. Preliminary Conclusions
  14. Acknowledgement

Introduction

In my absence from reviewing, another popular premium “budget” maker that has come on the scene is Sofirn. Making a series of affordable but powerful lights, I was curious to give them a try. So I purchased their popular compact 1×21700 model, the IF25A.

Note that this light has been around for a while now, so its performance may not be quite as high as some of their newer offerings. And my sample was purchased last fall – it took me awhile to get around to it, given all my requested reviews.

The IF25A is quite a tiny little tank of a light, and features 4x Luminus SST20 emitters. The light comes with a choice of either warm (4000K) or a cool (6500K) white LEDs. This review is of the cool white IF25A, in order to compare with other lights configured for maximum output.

Note this will be the second light I’ve tested that uses the open-source Anduril user interface (although I know it uses an early implementation of Anduril 2). Let’s see how the light performs in my testing.

Manufacturer Specifications

Note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results.

FeatureSpecs
MakerSofirn
ModelIF25A
Emitter4xSST20
Tint6500K
Max Output (Lumens)4,000
Min Output (Lumens)-
Max Runtime-
Max Beam Intensity (cd)-
Max Beam Distance (m)420 m
Mode Levels5 + Ramp
FlashingStrobe
Battery1x21700
Weight (w/o battery)99 g
Weight (with battery)-
Length106.4 mm
Head Diameter35 mm
Body Diameter35 mm
WaterproofIPX-8

Package Details



The IF25A comes in typical cardboard box, with fairly simply background illustrations and basic light details (I know some of the newer Sofirn models come in fancier packaging). Inside, I found:

  • Sofirn IF25A flashlight
  • Sofirn-branded 4000mAh 21700 battery (note some distributors may include a higher-rated cell)
  • A 18650 battery sleeve
  • Wrist lanyard
  • USB-C Charging cable
  • 2 Spare O-rings
  • Manual

It’s a decent package for a budget build. I would have liked a pocket clip and a higher capacity cell though, to match the competition (again, newer versions may come with a higher capacity cell). I do appreciate the USB-C charging cable – I have plenty of these lying around, but it always nice to see one included in a budget package.

Build


From left to right: LiitoKala 21700 (5000mAh), Fenix ARB-L21-5000U 21700 (5000mAh), Sofirm IF25A, Fenix E35 v3, Convoy S21E, Imalent MS03, Armytek Wizard C2 Pro Max, Acebeam E70, Nitecore P20iX, Nitecore MH12SE, Lumintop D3, Convoy M21F.







The IF25A is shorter than most lights in this class, despite the multi-emitter head. Despite that, it actually feels very robust, with a nice thick body. A surprisingly tiny but substantial build at the same time.

There is a side-mounted electronic switch on the side of the light near the head, with a grippy rubber cover that still allows the red and green LEDs underneath to shine through. Feel and traverse of the electronic switch is good. Note that by default the switch shines a constant low output dual-green when the battery is connected but not in use or charging (brighter green in those conditions). I initially found this constant “locator” feature is a bit annoying – but you can turn it off, or switch it to a brighter green (which actually has an important potential use – scroll down to User Interface for a discussion).

The button also shines a bright red when charging the battery through the light’s integrated USB-C charging port. The port is located on the opposite side from the switch, with a thick rubber cover. I found the cover to fit rather tightly, making it hard to full depress. But I suppose that should help with waterproofness if you can press it down enough.

I always recommend you keep a light stored locked out when not in use. Thanks to the anodized tailcap threads, you can do this easily on the IF25A by a simple twist of the tailcap. Threads are square-cut, and well lubricated. The light can tailstand stably, thanks to the side cut-outs for the wrist lanyard.

There is no actual knurling on the light, just a series of cut-outs at various points. Combined with somewhat glossy anodizing, this makes the light fairly slippery in use – I would have preferred some knurling elements. Note the light can also roll fairly easily, although the slightly flared tailcap helps a little bit with this (as does the rubber port cover). The anodizing seems in good shape on my sample, but I suspect it is only the thinner type II, given the price point.

Note that no pocket clip is included, and it would be a challenge to carry the light that way given the wider head and flared tailcap. Personally, I would have preferred a narrower tailcap and a clip option, since I don’t think thin wrist lanyards are of much use. Not a bad physical build by any means, but it does feel and look somewhat budget. I also find it a bit too short, but I have larger than average hands.

My sample came with a Sofirn-branded standard-sized 4000mAh 21700 battery (higher capacity may be sold by some vendors), with a slightly raised flat-top (also called a wide button by some).

A battery sleeve is also included, in case you want to use older 18650 cells (again, a nice touch in a budget light). I suspect a button-top would also work fine in the light, but it would need to be compact given the small size here (and certainly, none of those 21700 cells with built-in charging ports would fit). Note there is no spring in the head, just a flat contact disc (which helps explain the more compact length).



The IF25A uses 4 non-frosted TIR optics instead of individual reflectors, allowing the head be quite a bit shorter than most. I actually recommend the use of TIR optics for multi-emitters, as it tends to minimize beam artifacts. It also shines a generally “smoother” beam, with less differentiation between hotpot and spill. The beam looks reasonably clean on my sample, with just a few artifacts.

Note that I did observe some tint shifting on the lower levels (i.e., the lowest output has a definite greenish hue). This is not uncommon on current-controlled lights (e.g., Fenix), but is particularly noticeable here.

The bezel is flat black aluminum, with no crenelations – so, it can headstand stably, but you may not be able to tell if the light is on. I don’t see any form of AR coating on the lens.

There is a very interesting option with this light, using the switch indicator (green LEDs) when the battery and tailcap are connected. As I will explain below, you can increase the output of the default setting, giving yourself in essence an extra “moonlight” mode. Here is what it looks like, close-up on a white wall in the dark (not really this bright, using my cellphone’s auto-adjust mode):

Locator

The green is very even and surprisingly bright with dark-adapted eyes. Scroll down for more details on how to configure.

User Interface

The IF25A uses the open-source Anduril user interface (UI). Although the site I bought it from describes (and displays) the original interface of the inaugural Anduril release, I can confirm that my sample actually uses Anduril 2 (just like the Lumintop D3 I previously reviewed). I understand from ToyKeeper that it is actually an early implementation of it.

Anduril has two distinct UIs mode sets: Simple and Advanced. The labels are a bit misleading, as both are fairly sophisticated – it is just that the Advanced UI has a lot of extra options not available on the scaled-down Simple UI. Advanced UI also has an option for a discrete Stepped level mode, in addition to the continuously-variable smooth Ramping mode (which is the only mode present on the Simple UI).

To switch from the default Simple UI to Advanced UI, you need to do 10 clicks from Off, with a hold on the 10th click.

It’s easier to show the UIs rather than explain them in words, so here is a common pic:

ui-diagram

You can also download a fully described text manual here.

Like the Lumintop D3, my IF25A only has 5 discrete Stepped modes in the Simple UI (all 7 show up under Advanced UI though). Since most people are likely to leave it in the Simple UI, I’ve gone with 5 discrete levels my tables, and labelled L1-L5 as Moonlight, Lo, Med, Hi and Max/Turbo.

Again, check the image and link above for more info, but here is a simplified description of the UI to get you started.

From OFF:

    • Press-and-hold: Turns On in lowest output, in either Ramping mode or Stepped mode depending on which mode is enabled (and which UI you are in)
    • Single-click: Turns on in last memorized mode used (Ramping or Stepped)
    • Double-click: Turns on to Turbo (aka the Ramping max output)
    • Triple-click: Battery check (voltage read out a single time)
    • Triple-click-and-hold: Special strobe modes, but only when in Advanced UI (remembers last strobe mode used)
    • 4 clicks: Lockout mode. In lockout mode you have different options available:
      • Press-and-hold: Momentary Moonlight
      • Double-click-and-hold: Momentary Low
      • 4 clicks: Turns On in memorized output level
      • 4 clicks and hold: Turns On in the lowest level
      • 5 clicks: Turns On in Turbo
      • 10 clicks and hold: Configure the lock timeout threshold (in Advanced UI only), allowing you to pre-set the timeout time of the lock.
    • 7 clicks: (Advanced UI only) Enters auto light config for the button switch (“AUX/Button LEDs”). There are four modes you can switch between; constant low, blinking low, off, constant hi. Click 7 times again to advance to the next option, in sequence. The light auto-memorizes the last option you select. This allows you to use the switch LEDs as an impromptu “green moonlight” mode, as explained below.

From ON:

  • Press-and-hold: Ramps up (or Steps up, depending on the mode). Ramps/steps down if you do it again.
  • Single-click: Turns Off
  • Double-click: Jumps to Turbo
  • Double-click-and-hold: Ramps down (or Steps down)
  • Triple-click: Switch between Ramping and Stepped modes (in Advanced UI only)
  • 4 clicks: Lockout mode (see above for options)

Mode memory:

Yes, the circuit memorizes the last constant On output level in either Ramping or Stepped modes.

Strobe/Blinking modes:

Yes, quite a few actually. The strobe/blinking modes are accessible from Off with a triple-click-and-hold, but in Advanced UI only. You can switch between strobe/blinking modes with 2 clicks, in the following sequence (see testing results below to see what these look like):

  • Candle mode
  • Bike flasher
  • Party strobe
  • Tactical strobe
  • Lightning

Low voltage warning:

Sort of. In operation, the light drops in brightness in steps, and runs for an extended time at a very low level. Apparently it shuts off when the cell is ~2.8V (although I haven’t run it that long to confirm). I haven’t noticed any change in the switch LEDs to indicate low battery voltage (which seems like a missed opportunity, given they have red and green LEDs under there).

Lock-out mode:

Yes. In either Simple UI or Advanced UI, lockout is accessed by 4 clicks from On or Off (repeat to unlock). The lockout mode is unusual with Anduril, as it actually enables momentary operation in the Moonlight/Lo modes. There are other lockout modes available, as explained above. As always though, I recommend you physically lock out at the light at the tailcap, if you want to guarantee no accidental activation.

Temperature check and thermal calibration mode:

This is a little complicated (and beyond the needs of most users), so I will just refer you to the diagram from the manual above. With default settings, I find it steps down fairly quickly due to heat (unsurprising, give low thermal mass in the head). I have not tried to reconfigure my sample.

Reviewer Comments:

Anduril is a fairly sophisticated setup – a choice of Simple or Advanced UI, generally well thought out. Of course, you will never please everyone, and many may prefer a slightly simpler interface (e.g., the Convoy S21E), or even very basic one (e.g., Acebeam E70). While I can see flashaholics enjoying some of the extra items, some of them are really novelties (e.g. candle mode and lightning storm are particularly well done, but when would you practically ever use them other than as a party trick?). At the end of the day, I expect Simple UI is fine for most users. That said, the Stepped mode and bike strobe are something that many could use, so it’s nice to have them as options in the Advanced UI.

One of the main advantages of Anduril in a build like this is the ability to independently control the green LED emitters under the switch cover. By keeping the constant-on default setting (or increasing to brighter green), you can basically turn this into an additional “green moonlight” mode on the light. Simply use the light as a twisty: tighten the tailcap for moonlight and access to all the main modes, loosen the tailcap for a physical lock out. 🙂

Circuit Measures

Pulse-Width Modulation (PWM):

There is no sign of PWM on any level, the circuit appears to be fully current-controlled.

That being said, my oscilloscope was able to detect high frequency noise at all levels except max output, as depicted below. Note that these are not actually a concern, as they are not visible to naked the eye – the light remains flicker free in actual use. But I’ve noticed upon my return to reviewing that a lot of “budget” circuits are showing detectable signs of circuit noise. Using the Simple UI’s 5 discrete Stepped levels:

Level 1 (Moonlight):
L1

Level 3 (Med):
L3

Level 4 (Hi):
L4

Level 5 (Max):
L5

As you can see, noise begins with L1, at ~9.2 kHz. For L2 through L4, noise frequency remains constant at ~15.4 kHz, but increases in amplitude as output levels rise (which is fairly common, as more light is being emitted) – except for L5, which is noise free, oddly. Noise at these super high frequencies is impossible to detect visually, and so again not a concern. I am just including for completeness, as I like to present all my findings.

Strobes:

Tactical Strobe:
Tactical

Tactical strobe is a fairly typical 10.1 Hz, although the light spends more time in the On phase than the Off phase on each cycle.

Party Strobe:
Party

Party strobe is a super-fast (and annoying) short pulse at 25 Hz. I don’t know what kind of rave parties the Anduril folks like to hold, but I won’t be attending any. 😉

Lightning Strobe:
LightningD
Lightning
LightningA
LightningB
LightningC

I’ve shown five consecutive 10-sec cycles above, so you can a feel for the frequency and intensity of light flashes. Lightning strobe is a fairly realistic lightning simulation, with variable intensity and time between flashes.

Bike Strobe:
Bike

Bike strobe is a nice, slow 1 Hz signalling strobe – but with with 4 rapid flashes on every signal (shown in more detail below).

D3-BikeB

Beacon:
Beacon

Beacon strobe is a slow 0.5 Hz.

Candle:
Candle

Candle strobe is a continuous flicker, of varying intensity (again, accurately simulating a candle).

Charging:

The switch button shines a bright red when the light is charging (switches to bright green when the charging is complete).

Resting voltage <3.0V

Resting voltage >3.0V

The IF25A has a two-stage charging feature (i.e., with a lower charging rate for when cells are heavily discharged). With a heavily depleted cell (<3.0V), the initial charging voltage is a relatively low 0.32A. Once the resting voltage of the cell >3.0V, the charging current jumps to ~1.6V. Over the next few mins, it will continue to slowly rise a bit higher.

Note that the light drops to a very low level when the battery is nearly depleted, but there is no specific low voltage warning that I’ve noticed (e.g., there is no warning flash, and the button LED remains green throughout when the light is on unless you disable that feature). It will apparently shut-off at ~2.8V, but I never ran it that far to find out.

Standby / Parasitic Drain:

I measured the standby current (with default low green switch LEDs active) as 78 uA, which is negligible and not a concern (i.e., it would take many years to fully drain the cell). Regardless, I always recommend you lock the light out when not in use to prevent accidental activation (and cut any standby drain). A single twist of the tailcap will lock out this light, thanks to the anodized screw threads. And special bonus, this means you can use the tailcap twisty as a de facto “green moonlight” mode with the switch LEDs.

Emitter Measures

This section is a new feature of my reviews, where I directly measure key emitter characteristics in terms of colour temperature, tint, and colour rendition. Please see my Emitter Measures page to learn more about what these terms mean, and how I am measuring them.

As explained on that page, since I am using an inexpensive uncalibrated device, you can only make relative comparisons across my reviews (i.e., don’t take these numbers as absolutely accurate values, but as relatively consistent across lights in my testing).

As with all my reviews, the reported CCT and Duv measures above are for the first stable output mode without stepdown – which, in this case, is L3 (Med) on the Stepped Simple UI. The key measures above are the colour temperature of ~5265K, and the very noticeably positive tint shift (+0.0174 Duv) to green-yellow at this temperature.

For CRI (Ra), I measured a combined score of 59 on this level.

These values are very consistent with Luminus SST emitters, and match my visual experience of this light.

Given the subjectively stronger green tint-shift I noticed on the lower outputs, I decided to actually measure the Duv tint shift of each discrete Stepped level on the Advanced UI, as shown below.

L7: ~5225K, Duv +0.0169
L6: ~5240K, Duv +0.0178
L5: ~5165K, Duv +0.0192
L4: ~5000K, Duv +0.0223
L3: ~5000K, Duv +0.0222
L2: ~5030K, Duv +0.0218
L1: ~5095K, Duv +0.0211

As you can see, the CCT doesn’t change much (i.e., typically stays within ~5000-5250K), but the positive (green) tint shift is greater at the lower levels (L1-L4) compared to the higher levels (L5-L7).

Beamshots

All outdoor beamshots are taken on my Canon PowerShot S5 IS at f/2.7, 0.5 secs exposure, ISO 400, daylight white balance. The bend in the road is approximately 40 meters (~45 yards) from the camera. Learn more about my outdoor beamshots here (scroll down for the floody light position used in this review).

Click on any thumbnail image below to open a full size image in a new window. You can then easily compare beams by switching between tabs.


I did a second set of beamshots at this location more recently, showing two more relevant lights:

As you can see above, the beam pattern for IF25A is more on the floody side, as expected give the multi-emitters and shallow TIR optics.

Testing Results

My summary tables are generally reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. In addition to the links above, please see my output measures page for more background.

All my output numbers are based on my home-made lightbox setup. As explained on that methodology page, I have devised a method for converting my lightbox relative output values to estimated lumens. My Peak Intensity/Beam Distance are directly measured with a NIST-certified Extech EA31 lightmeter.

IF25A Testing Results

ModeSpec LumensEstimated Lumens @0secEstimated Lumens @30 secsBeam Intensity @0secBeam Intensity @30secsBeam Distance @30secsPWM/Strobe FreqNoise FreqCharging Current <3VCharging Current >3VParasitic DrainWeight w/o BatteryWeight with BatteryCCT (K)DuvCRI
L1 Moonlight-1.41.4---No9.2 KHz0.32 A1.6 A78 uA98 g163 g---
L2 Lo-7474---No15.4 kHz0.32 A1.6 A78 uA98 g163 g---
L3 Med-450440---No15.4 kHz0.32 A1.6 A78 uA98 g163 g5,2650.0174-
L4 Hi-1,6501,550---No15.4 kHz0.32 A1.6 A78 uA98 g163 g5,2800.016959
L5 Max4,0003,4003,05030,500 cd24,800 cd315 mNoNo0.32 A1.6 A78 uA98 g163 g---
Candle-------No0.32 A1.6 A78 uA98 g163 g---
Bike Strobe------1.0 HzNo0.32 A1.6 A78 uA98 g163 g---
Party Strobe------24 HzNo0.32 A1.6 A78 uA98 g163 g---
Tactical Strobe------10.1 HzNo0.32 A1.6 A78 uA98 g163 g---
Lightning-------No0.32 A1.6 A78 uA98 g163 g---
Beacon------0.50 HzNo0.32 A1.6 A78 uA98 g163 g---

My measured max output is considerably below the rated spec, as are my beam distance measures. The rated specs definitely seem inflated on this sample. That said, I do like the inclusion of the relatively low min output mode here (i.e., ~1.4 lumens). Not quite as low as I would like for Moonlight, but I’ll take what I can get given how rare actual Moonlight modes seem to be nowadays.

To see full testing results for all modern lights in my testing, check out my Database page.

Runtimes

As always, my runtimes are done under a small cooling fan, for safety and consistency. To learn more about how to interpret runtime graphs, see my runtimes methodology page.

Max

Hi

Med

For thermal reasons, both the (L5) Max and (L4) Hi runtimes quickly stepped down from their initial values to ~750 lumens or so, and stayed within a ~100 lumen range of that point for most of their extended runs (scroll down to see this with better resolution). You may be able to adjust this somewhat through the Anduril settings, but ultimately I suspect the low thermal mass of the light is the culprit here.

At the (L3) Med level, you get a semi-regulated runtime pattern (i.e., much closer to direct-drive over most of its run).

Something else you’ll notice in the full runtimes above is that the IF25A regulation pattern is quite “noisy”, demonstrating significant fluctuations in output over time (even at the “regulated” lower level). In practice, these fluctuations are not noticeable (i.e., they are actually fairly minor and slow over human perceptual timescales, and thus unnoticeable).

Here is a blow-up of the (L5) Max output runs, for both Ramping and Discrete Stepped, on a shorter time scale, to show you both the step-down and relative stability:

Max-extended

As you can see, there is no real difference between the discrete Stepped mode set and the Ramping (unlike some earlier reviews out there). It seems like Sofirn fixed that earlier issue.

To better show the effect of the “noisy” pattern above, here is a blow-up in even more detail, over a 2-min portion of the run when the changes in output were the most extreme (on the discrete Max output run):

IF25A-Max-extended

Again, these are not a concern as you will not be able to notice these kinds of subtle outputs changes in real life. Nevertheless, I would prefer to see more stable and consistent regulation across all modes, as the pattern above is a sign of a very basic budget circuit.

Which brings me around to the key point – overall efficiency of the IF25A appears lower than others in this class. Keep in mind my sample IF25A came with a 4000mAh battery, which is 20% lower capacity than most of the competition above. Still, the runtimes are  disappointing compared to lights with fully-regulated current-controlled circuits (e.g., the more expensive Nitecore P20iX, but even the budget Convoy M21F).

Part of this could be due to the relative efficiency of the multiple SST20 emitters (especially in a small head where heat management is an issue). But I doubt that is the main issue, as they are not being driven very hard at these lower “regulated” levels. It seems far more likely that the issue is with the driver. Which is a real shame, since Sofirn opted for the sophisticated Anduril UI – it would have been nice to have seen it paired with an efficient current-controlled circuit here.

I realize this IF25A model is getting a little long in the tooth now, but I still recommend Sofirn look into the improving both the regulation and the efficiency of the circuit on this model while it is still available.

Pros and Cons

ProsCons
Comes with the sophisticated Anduril UI, which has both simple and advanced options.Light steps down quickly on Max/Hi levels to a relatively low ~750 lumens for the remainder of the runtime (for thermal reasons)
Small and sturdy physical build.Driver output efficiency is below average for the class, consistent with entry-level budget lights.
Relatively floody beam, without too many artifacts from the multiple emitters.Regulation pattern is not impressive, both in terms of its relative spiky "noise" pattern, and semi-regulated appearance.
Thanks to the configurable UI, you can use the green LED switch indicator as an effective Moonlight mode.Rated specs for max output and beam distance are over-inflated in my testing.

Overall Rating

Preliminary Conclusions

The Sofirn IF25A is a serviceable build, with a decent (and sophisticated) user interface with a floody beam profile. It is a particularly compact yet sturdy light, which should appeal to many. That said, I would like to have seen a bit more refinement in the physical build (e.g., actual knurling, less-flared tailcap with pocket clip, etc.).

I realize this is an older model that has been around for a while, so it may not be entirely fair to compare it the newer competition. But the overall impression I have is one where they consistently skimped a bit on many aspects of the light. While each one may not seem like a big deal, the overall effect adds up over time. The most significant one is the circuit – both regulation and efficiency were sub-par, consistent with the most basic budget builds (yet many do better, as shown above). I find increasingly that this is something that differentiates the most entry-level budget lights from the intermediate or premium ones. At the end of the day, I find circuit performance really matters to me.

This is also an example where the rated max output and beam distance specs are clearly inflated. Since my return to reviewing, I’ve generally been pleasantly surprised to see much better concordance of my testing results to the rated specs (compared to the Wild West of my early days of reviewing). So when I see a clear mismatch now, as in the case of this light, it leaves a poor impression.

All scoring is relative, and bound to be a bit idiosyncratic, but I initially gave this light 3 stars overall. I’ve since upgraded that to 3.5 stars, as I find the green switch LEDs (especially set to high) to act as a very serviceable “green moonlight” mode. This is one of the plusses of having the sophisticated Anduril 2 UI, combined with a reasonable initial minimum and max output levels on the main emitter. But again, Max/Hi levels step down quickly to ~750 lumens for thermal reasons – which is a bit lower than the competition. And the main beam tint on all levels below Max/Hi is decidedly green on my sample.

The build quality seems relatively decent for a budget brand, and with a few noticeable refinements, this light could easily move into a higher tier. The quality and features inspire enough hope that I am looking forward to reviewing additional Sofirn lights.

Acknowledgement

The IF25A was purchased through an online vendor from China (aliexpress). As always, all opinions are my own and the light received the same rigourous and objective testing as all other lights that I have reviewed. At the time of review, this light retails for ~$35 USD (~$45 CDN).

Fenix E35 v3

The Fenix E35 v3 is a very compact every-day-carry style flashlight, featuring a moderately high output emitter and running on an included single 21700 battery. A TIR optic provides for very good throw.

  1. Introduction
  2. Manufacturer Specifications
  3. Package Details
  4. Build
  5. User Interface
  6. Circuit Measures
  7. Emitter Measures
  8. Beamshots
  9. Testing Results
  10. Runtimes
  11. Pros and Cons
  12. Overall Rating
  13. Preliminary Conclusions
  14. Acknowledgement

Introduction

Fenix is the maker that launched my interest in LED flashlights back in ~2006, so it seems only appropriate to start off my return to flashlight testing with their compact 1×21700 light, the E35 v3.

I recall the first generation E35 when it was released in 2012 – with a whopping max output of 235 lumens. 😉 At the time, it didn’t hold any interest for me. Around the time I wrapped up my reviews, a more interesting E35 Ultimate Edition, with an output of 1000 lumens, had come out. This third version (first released in 2020) is now rated at 3000 lumens, thanks to its Luminus SST70 LED emitter and included 21700 Li-ion battery.

Although this v3 model has been around for a couple of years now, it’s still a respectable contender in the compact 1×21700 EDC class that I plan to focus on in my upcoming reviews. So, let’s see what it has to offer.

Manufacturer Specifications

Note: as always, these are simply what the manufacturer provides – scroll down to see my actual testing results.

FeatureSpecs
MakerFenix
ModelE35 v3
EmitterSST70
Tint-
Specs Max Output (Lumens)3,000
Specs Min Output (Lumens)50
Specs Max Runtime50 hrs
Specs Max Beam Intensity (cd)14,400 cd
Specs Max Beam Distance (m)240 m
Number of Levels5
Flashing ModesStrobe
Battery1x21700
Weight (w/o battery)67 g
Weight (with battery)-
Length118 mm
Head Diameter26.5 mm
Body Diameter26.5 mm
WaterproofIP68 2m

Package Details

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The E35 v3 is shipped in standard retail store packaging, suitable for mounting on a display peg. This means you will need a pair of scissors or knife to open the sealed bubble plastic. Inside, you will find the following:

  • Fenix E35 v3 flashlight
  • Fenix 21700 USB-C rechargeable Li-ion battery (5000mAh)
  • USB-C charging cord
  • Pocket clip (attached)
  • Wrist lanyard
  • Spare o-rings
  • Manual, product brochure, and warranty card

It’s a reasonable package of accessories, but I do miss the old-style Fenix elasticized belt holster.

Build

20230402_162025
From left to right: LiitoKala 21700 (5000mAh), Fenix ARB-L21-5000U 21700 (5000mAh), Sofirm IF25A, Fenix E35 v3, Convoy S21E, Imalent MS03, Armytek Wizard C2 Pro Max, Acebeam E70, Nitecore P20iX, Nitecore MH12SE, Lumintop D3, Convoy M21F.

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The E35 v3 is among the most compact of the 1×21700 battery class of flashlights I’ve seen. The extra width of the 21700 cell (over standard 18650) is barely noticeable, and the light fits well in the hand.

The side switch is in a convenient location for traditional flashlight carry, as your thumb rests naturally on the switch. Note there is no tailcap switch, so there is no easy option to carry the light in overhand tactical stance (i.e., you would need to use your little finger on the switch if you did).

The light lacks traditional knurling, and has instead a series of fine concentric rings (which I have sometimes seen referred to as “reeling” instead of knurling). Frankly, I find these rather slippery here – I’ve definitely come across more substantial implementations of this design.

The pocket clip helps with grip, so I recommend you leave it attached (as there are few other protruding design elements). The pocket clip seems designed for downward carry, but you could in a pinch try to mount the light between the clip and body so that it is pointing upward instead. The clip is not physically reversible on the light.

Tailstanding is stable, and there are cut-outs along the raised side ridges for lanyard use.

Hard anodizing looks to be good quality (as is typical for Fenix), and is more on the glossy side than typical (I personally prefer more matte). Threads are anodized, so you can lock out the light by a twist of the head.

The power switch has a metal cover, with a clear centre to allow the integrated battery status LED to shine through (see User Interface below). Switch feel is decent for this style of light.

The light lacks a USB-C charging port on the body, but there is one built into the bundled battery. Given the extra length of these batteries, you’ll have to stick with ones that include such a port (and a pronounced button, as required in this case by the reverse polarity feature). Since the Fenix battery is quite long, I think you will find that few other brands will fit and work in the light (i.e., none of the other ones with integrated USB-C chargers that I have tried would work).

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The light apparently uses a Luminus SST70 LED – but not that you can easily tell, as the TIR optic obscures a clear view of the emitter die. I’m not generally a fan of TIR optics, but this one does an excellent job – a great balance of throw and wide spill, with no real colour distortions over the beam profile. Scroll down to see my beamshots below. That said, the lower output modes do have a noticeable green tint. This is not uncommon on Fenix lights, as constant-current drivers tend to produce more of a green hue at lower drive settings.

The bezel has a copper-colour ring that is completely flat (i.e., no crenelations). So if you lay the light down on its head on a flat surface, you may not be able to easily tell if it is on.

There is a reverse polarity feature in the head, so only true button-top cells will work in the light. I tried a few other 21700 cells, and none would activate the light.

Overall, I find this to be a good looking light with decent ergonomics and a great beam pattern. It fits well in the hand, but is a bit slipperier than I would like. A nice build in the compact 1×21700 EDC class.

User Interface

The E35 v3 uses a single side-mounted switch to control the flashlight. Available constant output modes, as per the manufacturer labels, are: Eco, Low, Medium, High, Turbo. There is one blinking mode outside the main sequence: Strobe.

From OFF:

  • Press and hold 0.5 sec: Turns ON (constant output)
  • Press and hold 2 sec: Strobe
  • Single click: Battery status
  • Double click: Lockout
  • Triple click: n/a

From ON:

  • Press and hold 0.5 sec: Turns OFF
  • Press and hold 2 sec: Strobe
  • Single click: Cycle through Eco to Turbo, in repeating sequence
  • Double click: n/a (it just cycles through the constant output modes)

Mode memory:

Yes.

Low battery warning:

Yes. The indicator LED under the switch will show the remaining power as follows; Solid Green (85-100%), Flashing Green (50-85%), Solid Red (25-50%), Flashing Red (1-25%). It is bright without being obtrusive.

Reviewer Comments:

I really don’t like this interface. I find clicking to advance modes to be counter-intuitive, and I kept advancing to the level every time I tried to turn the light off during my testing. I can normally live with press-hold for on (although prefer single click). But in this case it was ruined by putting strobe as the extended press-hold. So, if you hold the button down for a fraction of a second too long (when either trying to turn on or off), you wind up strobing yourself (which again happened to me repeatedly in my testing)!

Personally, I find this the worse of all possible worlds. I suppose if this is the only flashlight you own, you will get used to it eventually. But having handled an insanely high number of flashlights over the years, I find this sort of non-traditional pairing very annoying (especially for the strobe placement).

I am also sad to see the lack of a true moonlight mode (see Testing Results for more info). This is a real shame, reducing the usefulness of this light as an EDC.

Circuit Measures

Pulse-Width Modulation (PWM):

E35v3-Eco

There is no sign of PWM or circuit noise at any level. The light appears to be fully constant-current controlled. 🙂

Strobe:

E35v3-StrobeB
E35v3-StrobeC

Strobe alternates between two defined frequencies every second or so, measured as 14.7 Hz and 6.0 Hz in my testing. Certainly very disorienting!

Charging:

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Resting voltage <3.0V
E35v3-charging1

Resting voltage >3.0V
E35v3-charging2

The Fenix 21700 battery shows an initial low USB-C charging current of 0.12A when the cell is heavily depleted (<3.0V resting), which jumps up to 1.25A once the cell is >3.0V resting. This is a good design, and indicates a safe and reasonably rapid integrated charging circuit.

Standby / Parasitic Drain:

I measured the standby current as 35.5 uA.

This is negligible and not a concern for long-term battery life, but I always suggest you lock the light out when not in use to prevent accidental activation. A single twist of the head will lock out this light, thanks to the anodized screw threads.

Emitter Measures

This section is a new feature of my reviews, where I directly measure key emitter characteristics in terms of colour temperature, tint, and colour rendition. Please see my Emitter Measures page to learn more about what these terms mean, and how I am measuring them.

As explained on that page, since I am using an inexpensive uncalibrated device, you can only make relative comparisons across my reviews (i.e., don’t take these numbers as absolutely accurate values, but as relatively consistent across lights in my testing).

The key measures above are the colour temperature of ~5160K, and the very noticeable positive tint shift (+0.0199 Duv) to green-yellow at this temperature.

For CRI (Ra), I measured a combined score of 61.

These results are consistent with high output Luminus SST emitters, and match my visual experience of this light.

Beamshots

All outdoor beamshots are taken on my Canon PowerShot S5 IS at f/2.7, 0.5 secs exposure, ISO 400, daylight white balance. The bend in the road is approximately 40 meters (~45 yards) from the camera. Learn more about my outdoor beamshots here (scroll down for the floody light position used in this review).

Click on any thumbnail image below to open a full size image in a new window. You can then easily compare beams by switching between tabs.



Testing Results

My summary tables are generally reported in a manner consistent with the ANSI FL-1 standard for flashlight testing. In addition to the links above, please see my output measures page for more background.

All my output numbers are based on my home-made lightbox setup. As explained on that methodology page, I have devised a method for converting my lightbox relative output values to estimated lumens. My Peak Intensity/Beam Distance are directly measured with a NIST-certified Extech EA31 lightmeter.

Fenix E35 Testing Results

ModeSpec LumensEstimated Lumens @0secEstimated Lumens @30 secsBeam Intensity @0secBeam Intensity @30secsBeam Distance @30secsPWM/Strobe FreqNoise FreqCharging Current <3VCharging Current >3VParasitic DrainWeight w/o BatteryWeight with Battery
Eco506969---NoNo0.12 A1.25 A35.5 uA68 g141 g
Low150200200---NoNo0.12 A1.25 A35.5 uA68 g141 g
Med450530530---NoNo0.12 A1.25 A35.5 uA68 g141 g
Hi1,2001,4001,350---NoNo0.12 A1.25 A35.5 uA68 g141 g
Turbo3,0003,0002,90015,150 cd13,710 cd234 mNoNo0.12 A1.25 A35.5 uA68 g141 g
Strobe3,000-----14.7 Hz / 6.0 HzNo0.12 A1.25 A35.5 uA68 g141 g

To see full testing results for all modern lights in my testing, check out my Database page.

Runtimes

As always, my runtimes are done under a small cooling fan, for safety and consistency. To learn more about how to interpret runtime graphs, see my runtimes methodology page.

E35-Max

E35-Hi

E35-Med

As you can see above, the E35 is extremely efficient at all levels tested, consistent with a good current-controlled circuit.

I know the runtime pattern looks rather “noisy” on Turbo, but this is not actually visible to the naked eye. To illustrate, here are the max output runtimes blown-up to show the first 8 minutes:

E35-Max-Expanded

And now, an even greater blow-up of 2 mins in the middle of the run:

E35-2min

The gradual rise, and somewhat faster fall, in output are not visible to the naked eye as they happen over quite a few seconds. For all intents and purposes, the output appears completely stable in actual use.

Pros and Cons

ProsCons
Outstanding current-controlled efficiency
No Moonlight mode
Excellent balanced beam profilePoorly thought out user interface, easy to strobe yourself when turning on/off
Good thermal management allowing for reasonably high output levelsSomewhat slippery design
Very compact light
Included high-capacity battery with fast built-in charge rate

An additional neutral comment (i.e., not necessarily good or bad) is that only true button-top cells will work in the light. This is due to the reverse polarity protection feature.

Overall Rating

Preliminary Conclusions

I was really expecting to be able to award this light a higher rating when it first arrived. Fenix’s current-controlled circuitry has always had top-notch efficiency, with some of the best runtimes in the business (which is true here too). Although the lack of a moonlight mode was always going to bring it down from top status though – this is a fatal flaw in an EDC light, in my opinion.

I can handle the minor annoyances I found in testing (like the slippery finish), given all its other positive (e.g., its compact size and lovely beam). But the user interface is just bonkers to me. Who makes you long-press to turn on or off, but then makes strobe a slightly longer press? This is a recipe to strobe yourself when turning on or off (which I did repeatedly). Also not a fan of click to advance modes (i.e., easy to forget, so you wind up jumping to a higher level when you meant to turn off). Sorry, but this lack of forethought turns what is an otherwise top quality package into one that is just above average overall.

But it is all relative in the end. If you the user interface makes sense to you, or you figure you can get used to it, this light does have a lot to offer. The relatively high (and well-managed) output levels, the excellent runtime efficiency, and great beam pattern make it a serious contender in the the ultra-compact 1×21700 class of flashlights.

Reviewer’s Note: Between the time of my purchase and this review, Fenix has released a slightly updated version known as the E35R. But this has very minor tweaks – a tiny bump in max output to 3,100 lumens, inclusion of a USB-C charger on the light itself instead of the battery, slight body change with magnetic tail, and minor UI tweak for lockout. I doubt performance would be meaningfully different to what is described here, and none of the changes affect my conclusions about handling or the interface.

Acknowledgement

I personally purchased this light from a local dealer. This review has not been sponsored in any way. At the time of review, this light retails for ~$75 USD (~$105 CDN).