Sofirn SP31 V3 Tactical Flashlight Review
The Sofirn SP31 V3 tactical flashlight is a nice update to this Sofirn light. The update uses a Luminus SST-40 and still has a dual-switch interface. Read on!
Official Specs and Features
Here’s a link to the Sofirn SP31 V3 tactical flashlight product page.
Versions
Only one version of the v3 is available, but you can buy it with or without the 18650 cell. Of course, there are older versions of this light, though.
Price
Without the cell, the Sofirn SP31 V3 tactical flashlight sells for $24.99. The cell adds just $2, so it’s very reasonable to grab a cell, too!
There’s a discount code, too! Here’s the code: SOFIRNSP31
What’s Included
- Sofirn SP31 V3 tactical flashlight
- Sofirn 3000 mAh 18650
- Charge cable
- Lanyard
- Spare o-rings (2)
(I did not get a manual with this package! You probably will.)
Package and Manual
I did not get a manual with this package! You probably will.
Build Quality and Disassembly
Compared to V2 of the Sofirn SP31 tactical flashlight, the V3 has a much nicer build quality. There’s not any specific reason – it’s just nicer. My review of the Sofirn SP31 V2 tactical flashlight was 5 years ago, though, and Sofirn has definitely stepped up their game.
The cell tube is not reversible (threads are longer on one end). The threads are also anodized, which means locking the light out mechanically requires a very short twist. In fact, the tailcap doesn’t even come off this light!
Both head and tail have thick springs.
Size and Comps
Officially 25mm x 25.2mm (body diameter) x 122mm (length). 4.23oz with cell.
If the flashlight will headstand, I’ll show it here (usually the third photo). If the flashlight will tailstand, I’ll also show that (usually in the fourth photo).
Here’s the test light with the venerable Convoy S2+. The version below is a custom laser-engraved Convoy S2+ host by GadgetConnections.com. I did a full post on an engraved orange host right here! Or go straight to GadgetConnections.com to buy your Convoy S2+ now!
Also above is the light beside a TorchLAB BOSS 35, an 18350 light. I reviewed the aluminum version of that light in both 35 and 70 formats. I also reviewed that specific edition, the “Oveready BOSS FT Collector Vintage Brass” 35. I love it!
Retention and Carry
The first line of carry is the pocket clip, which isn’t reversible. Friction fit, and allowing only bezel down carry. The whole tailcap sits out of the pocket using this clip – over an inch! That’s much too much sticking out of the pocket.
The second option is the lanyard, which attaches to the tailcap. It’s also possible to connect it on the pocket clip, but I’d stick with the tailcap.
Power and Runtime
The SP31 V3 is powered by a single Li-ion cell. Sofirn includes a Sofirn branded 3000mAh 18650, which was used for all testing of this light. Since the light has springs on both ends, any type 18650 should work just fine.
Runtimes are below. There are three of them – the highest three levels. Performance looks pretty good on high and lower, but Turbo steps down at around 30 seconds.
In each case, the switch indicated when the cell voltage was low and then the light shut off.
Charging
Unlike previous iterations of the SP31, the SP31 V3 has built-in charging! There’s a USB-C charging port in the head.
A USB to USB-C charging cable is included.
Charging isn’t especially quick and doesn’t terminate too cleanly – the charging just trails off. The cell doesn’t get overcharged though, so that’s fine. And also, charging is essentially complete after around 4 hours at most.
Modes and Currents
| Mode | Mode Claimed Output (lm) | Claimed Runtime | Measured Lumens | Tailcap Amps |
|---|---|---|---|---|
| Turbo | 2000 | – | 1431 (0s) 1378 (30s) |
4.89 |
| High | – | – | 706 (0s) 705 (30s) |
1.59 |
| Medium | – | – | 240 | 0.43 |
| Low | – | – | 12.7 | 0.02 |
| Eco | – | – | 0.5 | [low] |
A bunch of this is empty because I didn’t get a manual. When Sofirn publishes a manual maybe someone can tag me and I’ll update the output claims, etc. Thanks!
Pulse Width Modulation
There’s no real PWM here except on Low, which is fast enough that you don’t have to worry about it unless you’re a pigeon!
Here you can see a “baseline” – a chart with almost no light hitting the sensor. Then there’s the Ultrafire WF-602C flashlight, which has some of the worst PWM I’ve seen. It’s so bad that I used a post about it to explain PWM! Here are multiple timescales (10ms, 5ms, 2ms, 1ms, 0.5ms, 0.2ms) to make comparing this “worst” PWM light to the test light easier. That post also explains why I didn’t test the WF-602C at the usual 50us scale.
User Interface and Operation
There are two switches on the Sofirn SP31 V3 tactical flashlight. The tail switch is mechanical forward clicky. The dome on the switch is big and grippy but does not protrude enough to prevent tailstanding.
The other switch is on the head and is an indicating e-switch. It’s nicely clicky and has very good action. The indicator in the center of the switch can be red or blue (blue seen below).
One notable thing about the indication on that switch is that it indicates the battery charge level for 5 seconds every time the tail switch is turned on.
Blue = “Enough power”
Red = “Short of power”
Flashing red = “running out of power.”
Here’s a UI table!
| State | Action | Result |
|---|---|---|
| Off | Click Tail Switch | On (Mode Memory) |
| Off | Click Side Switch | No Action |
| Off | Half-press Tail Switch | Momentary (Mode Memory) |
| On | Click Tail Switch | Off |
| On | Click Side Switch | Mode Advance (ascending) |
| On | Hold Side Switch | Strobe |
| Strobe | Click Side Switch | Strobe Group Advance |
| Strobe | Hold Side Switch | Return to the previous steady mode |
| On | Double Click Side Switch | No Action |
| Off | Hold Side Switch and click tail switch | On in Eco |
That’s really a pretty simple dual-switch UI. I like it too, because everything makes pretty good sense, and is intuitive. The strobe is also not too in the way.
LED and Beam
Sofirn has opted for a Luminus SST-40 emitter in the Sofirn SP31 V3 tactical flashlight. It’s cool white and uses a TIR.
LED Color Report (CRI and CCT)
Sofirn claims this emitter as a “6000K-6500K” and while it’s warmer than that (starting at around 5600K) it does cool off dramatically as the output gets higher. CRI is low in all modes and the Duv is positive, too.
Beamshots
These beamshots are always with the following settings: f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level and the beam hits the ceiling around 9 feet away.
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!
Summary and Conclusion
While version 2 of this light was a long time ago and this version should definitely be a nice upgrade, it also is a nice upgrade. In fact, it offers things we don’t even see in other much more costly “tactical” flashlights. For $25, this one’s hard to beat, even if you don’t consider it tactical. The Sofirn SP31 V3 tactical flashlight is a great way to get into a dual-switch EDC flashlight!
The Big Table
| Sofirn SP31 V3 tactical flashlight | |
|---|---|
| Emitter: | Luminus SST-40 |
| Price in USD at publication time: | $24.99 |
| Cell: | 1×18650 |
| Runtime Graphs | |
| LVP? | Yes |
| Switch Type: | Both |
| Quiescent Current (mA): | – |
| On-Board Charging? | Yes |
| Charge Port Type: | USB-C |
| Charge Graph | |
| Power off Charge Port | |
| Claimed Lumens (lm) | 2000 |
| Measured Lumens (at 30s) | 1378 (68.9% of claim)^ |
| Candela per Lumen | 11.8 |
| Claimed Throw (m) | – |
| Candela (Calculated) in cd (at 30s) | 656lux @ 5.107m = 17109cd |
| Throw (Calculated) (m) | 261.6 |
| Claimed CCT | 6000-6500 |
| Measured CCT Range (K) | 5600-6300 Kelvin |
| Item provided for review by: | Sofirn |
| All my Sofirn reviews! | |
^ Measurement disclaimer: Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.
What I like
- Low cost
- Great build quality
- Good user interface
- Shortcut to Eco
What I don’t like
- Cool to very cool CCT
- Low CRI
- USB-C charging weirdness
Notes
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