Sofirn SR15

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Sofirn SR15 Specifications & measurements

Brand & Model	Sofirn SR15
Flashlight category	General purpose
Battery config.	1*21700 li-ion
Switch type	Side
Dimensions:
Length	130 mm
Head diameter	40 mm
Weight with battery
LED & Beam
LED type	4* Luminus SFT-25R
High CRI	No
Focusable beam	No
Features
Onboard charging	USB C
Power bank	Yes
Specifications and measurements
Specified output	4,500 lm
Measured output (30sec)	2,840 lm
Max. measured output (turn on)	1,988 lm
Specified beam distance	510m
Measured beam distance (30sec)	462m
Specified beam intensity	67,500 cd
Measured beam intensity (30sec)	53,325 cd
Overall rating	4 stars
Review publication date	January 2025

Sofirn, as a household brand name for flashlights, has been a sort of quiet producer of late. Thanks to a recent resurgence in new releases, Sofirn has been thrust back into the spotlight, even though they haven’t enjoyed the same successes as their OEM partner Wurkkos. However, we’ve seen some bright spots of late, including the one up for review today.

This is part of the SR series, and follows the SR12 single LED light, but adds a 21700 cell and 3 LEDs for more output, creating the SR15. This is Sofirn’s newest light and adds some very nice features for a great value like we expect from them. Let’s see how ‘new’ it is though.

What’s in the package

The newer Sofirn lights are coming in nice packages, and so does the SR15. It’s a sleeved sturdy box with magnetic closure. You get some nice photos of the light and feature blurbs out back. Inside is well laid-out. Here’s what you get:

• Sofirn SR15
• Sofirn-branded 5,000 mAh 21700 li-ion battery
• USB type C to C charging cable
• Lanyard
• User manual
• Warranty card

This is a ready-to-go kit. Just unscrew the head, remove the isolator from the battery’s top, and away you go. The battery isn’t fully charged, so you’ll want to charge it a bit before any prolonged use, but it was sitting at around 3.8 volts out of the box. The lanyard is nice, with a cinch, and I’m really glad to see a proper USB C to C cable included so you can use the bidirectional charging. Thanks Sofirn!

The SR15 is a single cell quad LED general purpose light. It gets pretty bright (or dim) and can wear a lot of hats. For what it is, it’s pretty compact, about the same size as a Convoy M21H so it handles really nice and feels good in the hand. I’d say it’s still too big for EDC duty though, but will happily ride in a cargo pocket or clipped to something.

You get a one-way deep carry (detachable) pocket clip and there’s a lone lanyard point on the tail. The included lanyard did thread in somewhat easily. The tube has lots of texture for grip, and I had no trouble with grip in any position. Switching duties are handled by a side e-switch. It’s a somewhat proud grippy boot with a single central LED indicator for on and charge status. 

Opposite the switch is the USB C port. It’s sealed with the same cover the Wurkkos TS25 and TS26S use, so it’s been pulled from the Wurkkos/Sofirn parts bin.l That’s good because it’s a nice cover. The opening is a bit narrow, so larger USB C plugs might not fit (I had one that didn’t, with a tiny LED display). The switch feels good, with snappy positive clicks, so no complaints there. 

Sofirn (and Wurkkos) have really stepped up and their newer releases are much tidier in terms of build quality, fit and finish than older models. Overall, the SR15 is put together nicely. For price, plan on spending around $47.99 US with the battery direct from Sofirn, but you can get it cheaper on AliExpress and I’d say it’s a lot of light for cheap.

I don’t know if Sofirn was going after Acebeam specifically, but the E75 is the closest competitor. However, that one costs $80. Your $47.99 gets you a nicely milled  6061-T6 aluminum host and a nice matte black finish in type III HA. The whole tube unscrews (fixed tailcap) and batteries load from the front.

You get two springs for contacts, head and tail. They’re sufficiently stout and gold plated as well. Threads for the front are fully anodized, rectangular cut and smooth. They’re sealed with a single o-ring, and Sofirn gives an IP68 ingress rating, but test that at your own risk. 

For the warranty, Sofirn offers one commensurate with the price. From Sofirn: AT SOFIRN, WE BELIEVE IN OUR PRODUCTS.If your Sofirn product has any defect as the result of the materials or workmanship we want to make it right!

Within 30 days of purchase: Contact the original seller for repair or replacement.Flashlights: Within 1 year of purchase: Contact Sofirn for repair or replacement. Batteries: Within half a year of purchase.

In the first instance we attempt to resolve the issue. In the unlikely event of a faulty product we may advise customers to return the product to Sofirn for repair or replacement. Please Note: This warranty does not cover normal wear and tear, modifications, misuse, negligence, accidents, improper maintenance, or repair by anyone other than an Authorized retailer or Sofirn itself.

The SR15 fields the latest thrower LED from Luminus, the SFT-25R. You get four of them or a quad LED configuration. This is a 3535 size (XP footprint), domeless, round die LED. It’s 3 volts and is constructed on the same process as the other SFT LEDs, with a potted substrate containing 4 bonding wires.

The new design allows for higher drive currents and higher outputs. The round die measures about 2.1mm2, so it lends to high cd/mm2 and very high intensity. CCT (advertised) is 6000K to 6500K. The reflector is a quad SMO (smooth) cup unit with deep cups. It is made from plastic, but that’s okay since you can put a much more reflective and consistent mirror coating on a plastic reflector (plus it’s cheaper and easier to make).

In fact, Fenix uses one on the flagship LR80R. The beam? Well, this one’s a matter of preference. I don’t think the reflector is well-designed for these LEDs because it produces a very distinct X-shaped pattern (more like a large + sign) on a white wall, and it’s full of aberrations. This isn’t unheard of in quad reflectors, but, this one’s downright distracting and it’s visible outdoors as well. That aside, you get a usable beam with good distance, but I think an optic here or better-designed reflector would have been much better.

More details: 

• LED Type: Luminus SFT-25R
• High CRI: No
• Focusable beam: No

Spectral measurements:  

I used an Opple Lightmaster Pro to measure the flashlight at 1 meters distance. 

Mode:	CCT:	CRI Ra:	duv
Turbo	6167K	68.7	0.0033
Low	5478K	68.1	0.0077

Dimensions: 

Sofirn SR15	Millimeters	Inches
Length	140 mm	5.5 in
Head diameter	40 mm	1.6 in
Body diameter	25 mm	0.98 in

Dimensions are rounded to the nearest millimeter and the nearest tenth of an Inch.

Weight: 

Sofirn SR15	Weight in grams	Weight in oz
Without battery:	122 g	4.3 oz
With battery	190 g	6.7 oz

Weight is rounded to the nearest gram and tenth of an Oz.

Flashlight size comparison with its competition:

Group 1: Imalent R30C, Sofirn TS26S, Sofirn SR15, FireflyLite X4, Wurkkos TS25

Group 2: Manker E14 IV, Mateminco LT40, Sofirn SR15, Acebeam E75, Cyansky P50R

Group 3 reflectors: Mateminco LT40, Sofirn SR15, Acebeam E75, Cyansky P50R

One area Sofirn has stepped up is including regulated drivers. Yah, FET and linear drivers have their place, but for consumer-centric lights, you can’t do better than a fully regulated driver. The SR15 fields a buck driver for regulated output, lower temperatures, and more efficient operation. The UI is pretty typical for this type of light. It’s a smooth ramping UI with a stepped option, click on and off with Moon, Turbo and some blinkies.

Available modes: 

• Smooth ramping, or stepped ramping with Low, Medium, High, Moon, and Turbo

Available blinky modes:

• Strobe, SOS, Beacon

From OFF Stepped and Smooth Ramping:

• Press and hold: Moon. In STEPPED ramping, continuing to long press will start the stepped modes L-M-H)
• Single click: Turns on in last used brightness
• Double click: Turbo
• 3 fast clicks: Strobe. In Strobe, clicking twice activates SOS and Beacon
• 4 fast clicks: Electronic lockout

From ON:

• Press and hold: In SMOOTH ramp mode: Ramps up. The ramp starts at 1 Lumen and stops on Turbo (4500 Lumens). Release and hold to ramp down. IN STEPPED ramp mode, switches levels L-M-H-L. 
• 1 click: Turns off
• Double click: Turbo
• 3 fast clicks: Strobe. Double click again for SOS and Beacon
• 4 fast clicks: Switches between stepped and smooth ramping modes

Mode memory:

• Yes, remembers last used brightness up to Turbo in smooth ramping

Shortcuts:

• To Moon: Press and hold from OFF 
• To Turbo: From ON or OFF double click
• To Strobe: From ON in Moon mode, double click for Strobe

Strobe/blinkies

•  Strobe, SOS, and Beacon. Double click when is Strobe to switch to SOS and Beacon

Lock-out mode: 

• Yes. From OFF, four fast clicks to activate lockout. Momentary Moon mode is only available in lockout. Another four clicks to unlock

PWM

• Not visible with the naked eye

Additional/summary info on the UI: 

• Overall this is a serviceable UI from Sofirn, and I think it’s appropriate for the application. It’s not complicated like Anduril, and more straightforward for novice or new users. The fact you can switch from smooth to stepped ramping is nice too. All the click sequences make sense, and the brightness spacing is fine. The smooth ramping is the major sore spot here.
• I’ve encountered my share of ramping UIs over the years, ranging from fantastic (Anduril) to very good (some Haikelites), to usable (Wurkkos), and then poor. The SR15 falls under the poor. Here’s why:
• In smooth ramp, the light starts on Moon, and the ramp up from there is very fast, like Moon to Medium in about 1.5 seconds. The top of the ramp is Turbo as well, and I’d really like it if they had kept it at High so you could have the double click for Turbo. The ramp down follows the same algorithm, but starts slow and ends fast. Sofirn says there’s intelligent temperature control and LVP to keep everything safe-like.

For batteries, the SR15 uses a single 21700 cell and the test light shipped in kit form with Sofirn’s generic black dressed 5000 mAh flat top unprotected 21700. It’s rated for around 15 amps, which is sufficient for this light’s power demands. The batteries load from the front this time, like on the Wurkkos TS23. I tried flat top unprotected cells, button top unprotected cells, and a flat top protected cell.

All but the longest cells were a bit too long. Even with the stock cell, the top of the battery sticks out a good 10 mm from the top of the tube, so I had to compress and overcome a bit of spring tension to screw on the tube. You get onboard USB-C charging here, good for 5 volts 3 amps. C to C works fine, and you get bidirectional charging at the same output.

I used the SR15 to charge up the Acebeam E75 and it chooched along at around 10 watts. However, the battery would drain quickly if used that way, so I’d really only use it as an emergency power source. The battery took about 2.5 hours to charge, and added a hair under 4400 mAh.

Battery level indicator:

• Solid green: 70-100%
• Solid red: 30-70%
• Flashing red: 1% to 30%

Batteries	Details
Compatible batteries	Flat top, button top unprotected 21700 li-ion
Incompatible batteries	Long, protected or USB-C charging 21700s
Low voltage protection/warning	red light
Onboard Charging:
Onboard charging	USB-C
Power bank functionality	Yes
USB-C to USB-C charging	Yes
Max power of USB charger (port)	100 watts
Max power measured	14 watts / 5V 2.7A
Final battery voltage (charged)	4.23V
Avg. onboard charge time	2h 27min

Lumen measurements

How Lumens are Measured: Understanding ANSI FL1 Standards How Lumens are Measured: Understanding ANSI FL1 Standards: The ANSI FL1 standards specify that output in lumens should be measured 30 seconds after turning on, as this is the standardized time for measuring brightness according to the industry standard. This is why we focus on this part in our measurements. The ANSI FL1 standards require an ambient temperature of 22 ± 3°C. We record the ambient the ambient temperature to identify potential reasons for any observed discrepancies.

Lumens are measured in my 50 cm integrating sphere with a Digi-Sense 20250-00 data logging luxmeter. The sphere has been calibrated with a Convoy S2+ measured to 260 Lumens and the figures are within 10% of actual. No current testing this time due to the isolated current path. Outputs measured using the fully charged included 5000 mAh 21700 battery.

Mode	Amps at start	Specified output	Turn on	30 sec.	10 min.
Moon	N/A	1 lm	N/A	N/A	N/A
Low	N/A	70 lm	122 lm	122 lm	–
Medium	N/A	500 lm	553 lm	532 lm	518 lm
High	N/A	1,500 lm	1,477 lm	1,420 lm	717 lm
Turbo output	N/A	4,500 lm	1,988 lm	2,840 lm	710 lm

*Turn-on and 30 second measurements are done manually, while the 10-minutes readings comes from the runtime graph. This is our standard approach, though some reviewers may choose a different approach.

Ambient temperature during testing:

•  21 °C 

Parasitic drain:

• N/A µA/mA 

Moonlight was too dim to read and Turbo is way down from advertised. The output started low and ramped up, but nowhere near 4,500 Lumens, and I don’t know how Sofirn got 70 Lumens for Low because my reading is a lot higher.

Battery Life: Runtime graphs

How Runtimes are Measured: Understanding ANSI FL1 Standards About ANSI FL1 runtime standards: The runtime is measured until the light drops to 10% of its initial output (30 seconds after turning on). This does not mean that the flashlight is not usable anymore. The last column shows how long the light actually works till it shuts off. If there is a + symbol, it means that the test was stopped at that particular point, but the light was actually still running. This happens on certain occasions, with certain drivers, firmware, or batteries.

Lumens are measured in my 50 cm integrating sphere with a Digi-Sense 20250-00 data logging luxmeter. The sphere has been calibrated with a Convoy S2+ measured to 260 Lumens and the figures are within 10% of actual. I use a Digi-Sense 20250-92 data logging thermocouple for the temperature measurements. The probe is affixed to the head using kapton tape and uses the same 5 second sampling rate for logging.  Outputs measured using the included fully charged 5000 mAh 21700 battery.

Mode	Specified runtime	Runtime (ANSI FL1)	Time till shut off*
Medium	5h 30 min	4h 23min	4h 23min
High	3min+ 3h 30min	2h 55min	4h 10min
Turbo	60S+ 2h	2h 56min	4h 7min

*The last column reflects the total runtime until the light turns off. A “+” symbol indicates that the test was stopped at that point, but the light continued to run. This typically occurs with certain drivers, firmware, or battery types.

I’m glad Sofirn used a buck driver in the SR15, and we’re getting nice regulated output for every mode I tested. The outputs for Turbo are way down from spec, and the sustained output wasn’t very good. There is around 7 minutes of 1000 Lumens or better, followed by regulated output of 700 Lumens, then a drop to about 430 Lumens by 14 minutes.

That’s not too impressive for a quad. Sofirn makes good on the 60 second step down. High mode gives a little better output and sustained brightness, but not much, only about 55 seconds of 1000 Lumens or more followed by the same step downs as Turbo and the outputs tracking nearly identically. Medium looks good, but the runtime is about an hour short of spec with sustained output of around 500 Lumens. 

Turbo showed a bit of thermal fluctuation towards the end of the test, but overall the host never got too hot to handle even on Turbo, hovering around 50-55 C max. LVP hits and drops the output low before shutting down. The modes I tested didn’t dip into Moon-level output, and I didn’t see any blinking or any other LVP notifiers besides the blinking red switch LED. The battery read 2.9 volts after the test. 

For the following comparison, we see the SR15 holding down the middle of the pack, and it does okay compared to other quads, but it can’t match the Acebeam E75 for sustained output, and even the two FireflyLites with the very well regulated drivers beat it long term. I really think there’s room for improvement here.

Peak beam intensity and beam distance measurements

About Peak beam intensity: Understanding ANSI FL1 Standards About peak beam intensity The calculated value of distance in meters at which the flashlight produces a light intensity of 0.25 lux. (0.25 lux is about the brightness of a full moon shining on an object). This means that the intensity has decreased so much, it becomes difficult to see darker objects, or objects that don’t reflect light. The columns ‘Meters’ and ‘Yards’ use rounded numbers.

Beam distances are measured using a Uni-T UT383S luxmeter measured indoors at 5 meters using the fully charged 5000 mAh 21700 battery. Measurements taken at 30 seconds. The light was allowed to cool and the battery topped off between the High and Turbo measurements.

Mode	Specified intensity	Specified beam distance	Candela measured	Meters	Yards
Moon	9.1 cd	6 m	N/A	N/A	N/A
Low	1,650 cd	81 m	2,075 cd	91 m	100 yd
Medium	8,066.7 cd	180 m	10,625 cd	206 m	225 yd
High	19,125 cd	275 m	28,725 cd	339 m	371 yd
Turbo	65,025 cd	510 m	53,325 cd	462 m	504 yd

Moon was too dim and didn’t read at 5 meters. The rest of the measurements look okay, but Turbo is coming in low despite the other levels coming in high.

Ambient temperature during testing:

•  22 °C

Camera settings and distance: Photos taken with a Canon EOS R100 with Canon RF-S 18-45 mm STM lens. The camera is set to 0.3s, F5 ISO1600 and 5000K WB. The fence is 95 meters distant.

Beamshots of the following flashlights compared:

• Sofirn SR15
• Mateminco LT40
• Manker E14 IV
• Wurkkos TS25
• Wurkkos TS26S
• FireflyLite X4 FFL351A
• FireflyLite X4 SFT-25R

Please note that the following beamshots are mainly intended to showcase the beam pattern and beam quality, rather than overall performance. These images are typically taken directly after activation, and in different seasons or weather conditions, and therefore do not fully represent its overall performance. In few cases the camera settings are even different and therefore not meant for performance comparisons. For accurate performance metrics, such as output, beam distance, and runtimes, you need to look at the performance section of this review.

Disclaimer: This flashlight was sent to us for review at no cost by Sofirn. We have not been paid to review, nor have we been holding back on problems or defects.

Buy your Sofirn SR15 here

1lumen selects and reviews products personally. We may earn affiliate commissions through our links, which help support our testing.