Sofirn SC21

Introduction

There is a question that gets asked a lot in the torch world: Which is the best torch?

Many would argue that there is no definitive answer to that, as it depends on the requirements and the usage scenario. The best answer to the question, as it is asked is this: The best torch is the one you have on you when you need it.

To carry a torch at all times is a thing most people do not think about and only after one starts doing so, does one realise how incredibly useful it can be. But to do so, it has to be small enough to be inconspicuous and powerful enough to be useful.

Another requirement for most users, except size and power, is low cost, so it can be affordable and not a big deal if it gets scratched or damaged in the line of duty.

Today's review is about a light that ticks all those boxes, and then some: The Sofirn SC21.

The Sofirn SC21 is a small, powerful and budget friendly light that also features a high CRI emitter and onboard charging. Intrigued? Read on to find out more!

Unboxing

The Sofirn SC21 comes in a generic brown box with a sticker that specifies the contents.

Inside the box we find the extensive manual and the accessories. The manual is in many languages and the accessories include a clip, a lanyard, 2 spare O-rings and a charging cable. The charging cable is USB type A to USB type C and its length is 104cm, including the plugs.

The light itself comes protected in a bubble wrap bag. Inside the bag, along with the light, there is an orange label, explaining that there is an insulator inside the light that prevents the battery from making contact so the light can be shipped safely. That insulator needs to be removed before the light can be used.

The Sofirn SC21 is made of aluminium and features a side button with an LED charge indicator. On the opposite side of the side button there is a rubber flap with the USB logo engraved on it.

The flap can be opened to reveal a USB type C charging port.

The tail is magnetic and the magnet is strong enough to hold the weight of the torch in any orientation. There are also 2 lanyard holes and 2 respective grooves so the lanyard does not compromise the ability of the light to tail stand.

The business end of the Sofirn SC21 features a glass lens protecting an orange peel reflector. The emitter used in the Sofirn SC21 is a Samsung LH351D 5000K 90 CRI LED. It is good to see a neutral white, high CRI emitter used in an EDC torch. I expect this till take a toll on brightness and run times, but it is a sacrifice I am willing to make for better light quality.

The torch unscrews around the middle to reveal the battery compartment, with the battery already installed. An insulator is covering the driver side, preventing the positive terminal of the battery from making contact with it.

The positive terminal of the battery makes contact with the driver PCB through a brass contact point.

The negative terminal makes contact with the body with a good quality spring. The spring is not very thick but it should be more than capable of transferring the power required without significant losses.

The battery that comes with the Sofirn SC21 is a Sofirn branded 16340 Li-Ion button top battery, rated at 800mAh.

The clip can be placed on the back side of the light, as shown below. It allows for lens down deep carry and is bidirectional, which some people like as it allows clipping the light on to a hat and using it as a headlamp, but others dislike as it is not as secure as a unidirectional clip.

The end of the clip drags on the head of the torch when the two parts are unscrewed / screwed so I expect that over time it will damage the finish, unless it is carefully lifted to avoid that.

Quality

The milling quality and anodization are very good, without any sharp edges or visible defects. Even under close inspection the finish and knurling look good.

Specifications

The specifications of the Sofirn SC21, as found on the Sofirn website, are listed in the table below.

The Samsung LH351D 5000K 90 CRI LED is a high light quality choice, rather than a high brightness / high efficiency one and I agree with it. The company claims a maximum output of 1000 Lumen, which is a bold claim. We will test that. The throw is rated at 135m.

User Interface

The user interface of the Sofirn SC21 is designed to please both those that prefer a stepped mode torch and those who like ramping.

Out of the box, the light comes in stepped mode. The stepped mode works as follows:

• From OFF single click to turn ON.
• Press and hold to cycle through the main stepped modes (Low – Medium – High).
• From ON single click to turn OFF.

To change to the ramping mode (or back from the ramping mode to stepped mode), you need to do 4 fast clicks while the light is on.

The ramping mode gives you full flexibility to adjust the brightness steplessly from Moon to Turbo level and works as follows:

• From OFF single click to turn ON.
• Press and hold to change brightness steplessly (“ramp”).
• Ramping changes its direction when the button is pressed again within 1.5 seconds.
• The light flashes once when it reaches the lower or upper end of the ramp.
• From ON single click to turn OFF.

In either stepped or ramping mode:

• From OFF hold for 1 second to turn on at Moonlight level.
• Double click to activate Turbo mode from OFF or ON. While in Turbo mode, single click to return to the previously used mode.
• Triple click to activate Strobe mode from OFF or ON. While in Strobe mode, single click to return to the previously used standard mode, or press and hold to cycle through SOS - Beacon - Strobe.

The light features both electronic and mechanical lock out.

The electronic lock out works as follows:

• From OFF, 4 fast clicks to activate lockout.
• Another 4 fast clicks to deactivate lockout and turn the light on at the memorized level.
• When the light is locked, the main LED blinks twice when the button is pressed to show the status of being locked.
• While in lockout mode, hold the button to use Moonlight mode momentarily.

If you prefer a mechanical lock out, unscrewing the battery tube by 1/4 turn, will break the connection of the negative terminal of the battery to the driver.

The Sofirn SC21 also features mode memory, so it will turn on at the last used level (except Turbo).

Beam-shots

The beam pattern of the Sofirn SC21 is what can be expected from a Samsung LH351D emitter in a shallow, orange peel reflector. It provides a balanced beam with some throw and flood, perfect for EDC.

The hot spot is well defined and large and the spill is uniform without any artefacts, thanks to the OP reflector.

I tested the Sofirn SC21 outside, over a distance of 70m.

The following video shows a comparison of the Sofirn SC21 with the Olight Baton 3 and the Olight S1R Baton II. The Sofirn SC21 offers a more neutral and high CRI beam while the Olight torches have a cooler tint and low CRI but higher output.

Driver

The driver of the Sofirn SC21 provides constant current to the emitter on all modes. There is no PWM that my camera could detect on any output level. The driver also features Thermal Regulation, Reverse Polarity Protection and Low Voltage Protection.

Tint and Size Comparison

The tint of the Sofirn SC21 is neutral white, at 5000K.

In the comparison photo below, you can see the Sofirn SC21 in the middle, compared to the much cooler and greener tints of the Olight Baton 3 on the left and the Olight S1R Baton II on the right. The Samsung LH351D 5000K emitter used in the Sofirn SC21 is high CRI (90). The photo was taken with the white balance set to 5500K.

The length of the Sofirn SC21 is 73mm, which is 10mm longer than the two Olights. That is mostly due to the fact that it uses a reflector and a glass lens instead of the TIR optic used by the two Olights. This offers the advantage that the glass is much harder to scratch than the plastic TIR and does not burn like the plastic can if there is any debris on it, so I actually prefer it.

The USB C port also takes more space than the proprietary magnetic charging that Olight uses. As much as I like the magnetic charging system, there is something to be said for not having to carry around a proprietary cable.

Battery and Charging

The battery included with the Sofirn SC21 is a 16340, rated at 800mAh and I measured it at exactly 788mAh. The light has Low Voltage Protection and turns off when the battery voltage drops to 2.5V which is too low and will wear out the battery, so it should have been set higher. The battery's internal resistance was measured at 79mΩ. These measurements show that a high quality battery is actually included with this light.

The indicative LED on the switch of the Sofirn SC21 shows the level of the battery charge. Green means that the remaining charge is at between 100% and 70%, red that it is below 70% and flashing red that it is critical and the light will soon turn off. I would have preferred at least one intermediate indication between 70% and almost empty.

Charging the Sofirn SC21 is very easy. Just lift the rubber cover and insert the provided (or any) USB type C cable to charge the light. Both USB A to USB C and USB C to USB C cables can be used as well as any charger, including the ones that support PD. This is very convenient as you can charge the Sofirn SC21 with any USB C cable and charger you have at hand.

The indicative LED on the switch flashes red to indicate the light is charging. It turns green when the charging is completed, at 4.21V.

The company advertises that the charging of the Sofirn SC21 takes 1 hour, with a 5V charger, capable of providing 1A.

It actually took 1 hour, 28 minutes and 25 seconds to charge the included battery from 2.5V to 4.21V inside the Sofirn SC21. The maximum current drawn was 0.9541A, so a charger that can provide at least 1A is recommended. A charger is not provided with the light but you can use your phone charger.

A charging current of almost 1A for a 800mAh 16340 battery is rather high and despite being convenient as it charges the battery fast, it will take a toll on the battery longevity. That said, most lights do the same, including the 2 Olights we saw earlier.

Output & Runtimes

The Sofirn SC21 is rated at a maximum output of 1000 Lumen and 135m of throw.

I do not own a multi thousand dollar worth integrating sphere, just a logging Lumen meter and a home made integrating tube. The array is calibrated with 3 separate, professionally measured lights and gives me consistent results, but there is definitely room for error and deviations are to be expected.

The output of all modes as well as the respective run times are shown in the table below.

According to my measurements, Moonlight is 0.5 Lumen (instead of 1), Low is 17 Lumen (instead of 10), Medium is 93 Lumen (instead of 100), high is 323 Lumen (instead of 400) and Turbo is 848 Lumen at turn on (instead of 1000).

The maximum output (at turn on) of 848 Lumen is short of the advertised 1000 by about 15% but still very respectable for the size of the light and especially the fact that it uses a high CRI, neutral white emitter. Output at 30 seconds was 798 Lumen and at 1 minute the output was still 786 Lumen. At 2 minutes the output had decreased to 744 Lumen and then started to decline faster due to thermal regulation to reach reach 206 Lumen at 00:02:51, where it stabilized until the temperature dropped enough and the output rose to 307 Lumen (High) at 00:10:34. It then stayed at that level, with the temperature slowly rising, until at 00:27:54 thermal regulation decreased the output to 254 Lumen. The light remained at that output level until 01:01:45, when the temperature had dropped enough. It then tried to increase the brightness to 307 Lumen, which only happened momentarily as by then the battery did not have enough voltage to support that level of output. Therefore, the light stepped down to 91 Lumen (Medium) for about 6 minutes and then to 17 lumen (Low). It then sustained that output for as long as possible. Unfortunately, the light will not turn off when the battery can no longer sustain the Low output and the brightness just declines with the voltage. It would have been much better if the light just turned off when the battery dropped to that level as that way we would see only regulated output and the battery longevity would be better.

The following graph shows the first 10 minutes of the Turbo Full Runtime Graph in greater detail.

Turbo is good and impressive but is hardly the mode that is actually most used in a torch. Therefore, I decided to make a runtime graph for High.

The graph is self explanatory. The output is stable and regulated. It maintains High output for 58 minutes, then steps down to Medium for 6.5 minutes and then to Low for as long as the battery can sustain it. Again, we see there is no cut off when the battery can no longer sustain the Low output.

The following graph shows the first 10 minutes of the High Full Runtime Graph in greater detail.

The Sofirn SC21 is advertised to produce 4533cd and therefore have a throw of 135m. I measured 3488.16cd which means that the actual throw is 118m, about 12% less than advertised. This is to be expected as the maximum output measured was 848 Lumen instead of the 1000 Lumen advertised, which is about 15% less.

Comparison with Olight Baton 3 & Olight S1R Baton II

I was wondering how much of a disadvantage on brightness and efficiency does the high CRI emitter of the Sofirn SC21 introduce compared to lights that prioritize brightness and efficiency over tint and CRI. So, I decided to compare the above runtime graphs with those of the Olight Baton 3 and the Olight S1R Baton II.

It was clear from the tint comparison that the Sofirn SC21 offers a much more pleasant, less green and neutral tint than the two Olights and also much better colour rendition as it is 90 CRI instead of the 70 CRI Luminous SST40 emitters the Olights use.

As we can see in the comparative graph below, the Olight Baton 3 is by far the most efficient light, but also "cheats" a bit by setting its high output lower than the Olight S1R Baton II, to reserve power.

The Sofirn SC21 did surprisingly well, both in brightness and in efficiency considering the neutral tint and high CRI.

The following graph shows the first 10 minutes of the Turbo Full Runtime Comparison Graph in greater detail.

What is even more interesting is the much more realistic scenario of using the lights on High rather than Turbo. That way, the much hotter Samsung LH531D of the Sofirn SC21 does not need to step down due to thermal regulation and sits between the two Olights in brightness. It also outperforms the Olight S1R Baton II in run time, albeit while being less bright.

The following graph shows the first 10 minutes of the High Full Runtime Comparison Graph in greater detail.

There is no winner here, just 3 very good EDC lights, each with its advantages and disadvantages, according to the emitter that was selected and the programming of the driver. It does speak volumes though that the Sofirn SC21 is standing as equal amongst equals, with comparative advantages and disadvantages depending on preference and usage scenario, with 2 lights that cost twice what it does.

Current Draw

The Sofirn SC21 has a low parasitic drain that is below the ability of the clamp meter to measure. The Moonlight Mode only draws 10mA. The Low, Mid and High modes need 60mA, 197mA and 788mA respectively and Turbo required 2.83A.

Conclusion

The Sofirn SC21 is an small EDC torch that ticks many boxes. It uses a Li-Ion 16340 battery to power a 5000K, 90 CRI Samsung LH351D emitter and produce a maximum of 848 Lumen and 118m of throw (measured). This is indeed an excellent performance for a high CRI light with neutral tint and even though it falls short of the advertised 1000 Lumen and 135m, it is very respectable and more than enough for EDC purposes while the quality of the light is more than enough compensation for the reduced performance.

The driver is regulated and provides stable output with no PWM on any level. It incorporates Thermal Regulation, Reverse Polarity Protection and Low Voltage Protection. The only flaw in my opinion is that the low voltage protection only kicks in at 2.5V which is not good for the battery. It should turn off the light at around 3V.

The build quality and anodization are very good and the user interface is simple, intuitive and versatile, providing both stepped and ramping options.

The button is easy to press and incorporates an indicative LED which shows the battery level and also when the light is charging and when the charging is finished.

The Sofirn SC21 uses a glass lens and aluminium reflector combination which is much harder to scratch than a plastic TIR optic and does not melt if there is debris on the lens.

The tail cap is magnetic and the magnet is strong enough to hold the light at any orientation. The clip allows for lens down deep carry and is bidirectional so the Sofirn SC21 can be clipped to a hat to use as a headlamp.

The Sofirn SC21 can be purchased directly from the Sofirn Website and the cost at the moment this review is written is $23.99, including the battery or $20.99 without the battery. Shipping costs $3.99 and tax varies depending on the country of destination.

Let's list the Pros and Cons of the Sofirn SC21:

Pros

+ Value for money.

+ High CRI.

+ Neutral 5000K tint.

+ No PWM at any output level.

+ Glass lens and Aluminium reflector.

+ Aluminium Alloy construction.

+ Very good anodization and fit and finish.

+ USB type A to C and type C to C charging.

+ Fast battery charging, in less than 1.5h.

+ Low Voltage Protection.

+ Thermal Regulation.

+ Reverse Polarity Protection

+ Well balanced beam.

+ 16340 Li-Ion 800mAh (788mAh measured) battery included.

+ Battery level and charging LED indicator.

+ Simple and intuitive stepped and ramped UI.

+ IP68.

+ Bidirectional clip, which some users like as it can be clipped on to a hat to use as a head lamp.

+ Compatible with all button top 16340 batteries that can provide at least 3A.

Cons

- Low voltage protection turns off the light at 2.5V which is too low and can damage the battery and affect its longevity.

- Fast battery charging can affect battery longevity.

- Bidirectional clip, which some users dislike as it is not as sturdy and easy to use as unidirectional clips.

- The clip could scratch the finish over time.

- The battery level indicator LED could have more levels.

Thanks to Sofirn for providing the light for review

Polymeros Achaniotis 07/09/2021