Sofirn SC21 Flashlight Review
A new light like the Sofirn SC21 flashlight is a bit unusual. It’s a 16340 light! Add an indicating e-switch, a magnet, and more… Read on!
Official Specs and Features
Here’s a link to the Sofirn SC21 flashlight product page.
Versions
There is just one version of the Sofirn SC21 flashlight. It’s available as a kit, too though.
Price
Without the cell (“SC21 Alone”) the package is $20.99. With the cell (“SC21+Battery”) the package is $23.99. If you make a purchase, I recommend grabbing the kit – the cell is worth the extra $3. This light is available on Sofirn’s newly revamped website!
Short Review of the Sofirn SC21 Flashlight
For $21, the Sofirn SC21 flashlight is extremely hard to beat. The size is great – despite nearly everyone forgetting about 16340 cells, they still make for great EDC flashlights. Aside from size, this is a feature-packed light. Indicating e-switch, tailcap magnet, USB-C charging, and a nice reflector…. There are a couple of things I don’t care for so much, though.
Long Review
The Big Table
| Sofirn SC21 Flashlight | |
|---|---|
| Emitter: | Samsung LH351d (5000K, 90CRI) |
| Price in USD at publication time: | $23.99 |
| Cell: | 1×16340 |
| Turbo Runtime Graph | High Runtime Graph |
| LVP? | Questionable |
| Switch Type: | E-Switch |
| Quiescent Current (mA): | 0.11 |
| On-Board Charging? | Yes |
| Charge Port Type: | USB-C |
| Charge Graph | |
| Power off Charge Port | “with cell: all modes without cell: all modes except Turbo” |
| Claimed Lumens (lm) | 1000 |
| Measured Lumens (at 30s) | 769 (76.9% of claim)^ |
| Candela per Lumen | 5.8 |
| Claimed Throw (m) | 135 |
| Candela (Calculated) in cd (at 30s) | 236lux @ 4.504m = 4787cd |
| Throw (Calculated) (m) | 138.4 (102.5% of claim)^ |
| Claimed CCT | 5000 |
| Measured CCT Range (K) | 4700-5000 Kelvin |
| Item provided for review by: | Sofirn |
| All my Sofirn reviews! | |
^ Measurement disclaimer: I am an amateur flashlight reviewer. I don’t have $10,000 or even $1,000 worth of testing equipment. I test output and such in PVC tubes!! Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).
What’s Included
- Sofirn SC21 flashlight
- Sofirn 800mAh 16340 (standard button top)
- Spare o-rings (2)
- Charge cable (USB to USB-C)
- Lanyard
- Pocket clip
- Manual
Sofirn SC21 Flashlight Package and Manual
The manual is a booklet. But I disassembled it, scanned it, and broke down the pages just because of how much I <3 you all. Below is the full English manual.
Build Quality and Disassembly
First of all, let us not forget that this light is offered at $21. That’s a ridiculously low-cost light, especially for what all is on offer here.
Now there is a thing or two I don’t love about the build, but at $21, and being that it’s just personal preference, it’s very easy to overlook those. I don’t love the knurling. It’s very good knurling! It’s just … something. Sort of mismatched with the rest of the light design – I’m not sure we even need to see knurling on this light at all. Very minor point though!
Here’s the tailcap, which has a little bump out to house the magnet. The edge is also even with this bump out, and allows room for the lanyard holes.
Cooling fins in the head are minimal, but that’s ok. The light is drawing around 2.5A on turbo.
Here you can see that the bezel is smooth. It looks removable, but I was unable to remove it. I can’t say if this is because of threadlock or what.
The head comes off the body easily, over smooth anodized threads. Because of this anodization, it’s possible to mechanically lock the light out with a very light loosening of the head. I recommend this, as quiescent current is fairly high here.
Only the tail ens sports a spring; the head has just a brass button. I did not explore the option, but the spring looks to be removable, so you could remove the magnet if you wish.
Size and Comps
Dimensions
Length: 73mm
Body Diameter: 22.5 mm
Weight: 39g (Not including pocket clip or battery)
If the flashlight will headstand, I’ll show it here (usually the third photo). If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).
Here’s the test light with the venerable Convoy S2+. Mine’s a custom “baked” edition Nichia 219b triple. A very nice 18650 light.
And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light. I reviewed the aluminum version of that light in both 35 and 70 formats.
Here are a few other random lights I had laying around! Hanko Trident Full Twist in brass, Sofirn SC21, Torchlab BOSS 35, Okluma DC1 in aluminum. I haven’t reviewed this specific Okluma – maybe I should?
Retention and Carry
A friction fit pocket clip is included, but not installed by default.
This clip fits only on the tail end of the light but is a two-way clip. I have historically not loved two-way clips and this is no exception, but the execution here is fairly good. There’s a tradeoff being made though. The clip is short, which means it doesn’t get in the way of head removal. (This is good – the clip doesn’t scratch the head when twisting.) But the clip is short, so while using this on a cap will work, the Sofirn SC21 flashlight will protrude by almost half of its body length over the front of the bill. Pick your poison?
Also included on the Sofirn SC21 flashlight is a couple of lanyard hole attachment points. These are interesting because they feature a gap to allow tailstanding while the lanyard is installed.
The idea here is great, but in reality, the implementation is less so – just give me two holes for the lanyard to go through, as a Convoy S2+ has, and let’s call it good. Or maybe there’s some other explanation for this setup that I don’t yet know?
The tailcap magnet is easily strong enough to hold the Sofirn SC21 flashlight.
Power and Runtime
The Sofirn SC21 flashlight is powered by a single lithium-ion cell – in this case, a 16340. An appropriate cell is included – an 800mAh button top.
The cell is installed into the light in the usual way – positive end toward the head.
Runtimes follow. Turbo steps down fairly quickly, but not in such a way that it seems to be gaming the ANSI standard. In fact, Turbo drifts downward as cell voltage declines, and then finally steps down (likely) in response to the temperature created. Funny, after mentioning it in a recent review, we see the output modulate back up after the flashlight reaches an acceptably low temperature.
The next to levels of output show very flat output until the stepdowns.
Notably, on the test for Medium, I did not observe low voltage protection. The product page says “voltage detection, low power remind” but doesn’t state lvp. So I won’t say it’s a problem because Sofirn seems clear about it. But I’d much rather the light shut off at 2.7 or 2.8V or so… There’s no need for a light like this to not have lvp.
Charging
On-board charging is available and happens via this USB-C port in the head. A press-in cover protects the charge port.
Sofirn includes a quite nice USB to USB-C cable.
I tested the charge cycle with both USB to USB-C and C to C. The charge looks about the same for either, but it’s good to know that C to C works just fine.
Modes and Currents
| Mode | Mode Claimed Output (lm) | Claimed Runtime | Measured Lumens | Tailcap Amps |
|---|---|---|---|---|
| Turbo | 1000 | 1h | 769 | 2.54 |
| High | 400 | 1h | 308 | 0.67 |
| Medium | 100 | 4h | 84 | 0.16 |
| Low | 10 | 18h | 13 | 0.03 |
| Moon | 1 | 85h | 0.7 | 6.26mA |
Pulse Width Modulation
Weirdly, one mode seems to have PWM. I’m not able to see it though, so it seems acceptably fast.
For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor. Also, here’s the light with the worst PWM I could find. I’m adding multiple timescales, so it’ll be easier to compare to the test light. Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, with is 50 microseconds (50us). 10ms. 5ms. 2ms. 1ms. 0.5ms. 0.2ms. In a display faster than 0.2ms or so, the on/off cycle is more than one screen, so it’d just (very incorrectly) look like a flat line. I wrote more about this Ultrafire WF-602C flashlight and explained a little about PWM too.
User Interface and Operation
The Sofirn SC21 flashlight is controlled by a single switch. It’s an e-switch on the side of the head.
This switch also has indicating features – below it’s seen indicating red for low voltage. Notably, the switch will indicate for 5 seconds after the light is turned on, as follows:
Green: remaining battery power is good
Red: remaining battery power is poor (less than 30%)
Red Flashing: recharge or swap cell immediately.
There’s a surprising amount of travel on this switch. It’s also quite proud.
Here’s a UI table! Note that this user interface is just like the Sofirn SP35, which I reviewed previously.
| State | Action | Result |
|---|---|---|
| Off | Click | On (Mode Memory) |
| Off | Hold | Moonlight |
| On | Hold | Group 1: Mode cycle (Eco, Low, Medium, High only) Group 2: Ramp up |
| Any (except Turbo) | Double Click | Turbo |
| Turbo or Strobe | Click | Previous state |
| On | Click | Off |
| Turbo | Double Click | Moonlight |
| On | Click 4x | Switch between Group 1 and Group 2 |
| Any | Click 3x | Strobe |
| Strobe | Double Click | Strobe advance (Strobe, Beacon, SOS) |
| Off | Click 4x | Lockout |
| Lockout | Click 4x | Unlock |
| Lockout | Click | Main emitter blink 2x to indicate lockout |
| Lockout | Hold | Momentary Moonlight |
Why you’d want to double click from Turbo to get to Moonlight, I have no idea.
Group 2 (Ramping) is very similar to the above Group 1, except holding the switch will cause the light to ramp up. Loosening then holding the switch again within 1.5s will cause the ramp to switch directions. So it’s possible to ramp up or down. Double click still gets Turbo.
LED and Beam
One of the main important features of the Sofirn SC21 flashlight is that it features a Samsung LH351d emitter. This is a 5000K temperature, and I applaud the great choice here by Sofirn.
Sofirn didn’t go for “short” on the SC21 and used a nice deep reflector. This gives a great beam profile.
The bezel is flat with no shape, so light does not escape when headstanding.
Also, see here that the switch is indicating in green.
LED Color Report (CRI and CCT)
The readings on this SC21 show a CCT of 4700K to around 5000K and CRI above 90. Both of these are good.
Beamshots
These beamshots are always with the following settings: f8, ISO100, 0.3s shutter, and manual 5000K exposure.
Tint vs BLF-348 (KillzoneFlashlights.com 219b version) (affiliate link)
I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.
I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!
Conclusion
What I like about the Sofirn SC21 Flashlight
- Good to see a new 16340 flashlight available!
- User interface offers something for most users (ie ramping is there if you want it)
- Switch is easy to find
- Indicator on switch is very clear and clean
- Complete package is a very good and low cost
- USB-C charging (and also C to C charging works!)
- Good choice of 5000K emitter
What I don’t like about the Sofirn SC21 Flashlight
- Does not seem to have low voltage protection
- Two-way pocket clip
Notes
- This content originally appeared at zeroair.org. Please visit there for the best experience!
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