Convoy S21G Titanium Flashlight Review
The Convoy S21G titanium flashlight offers a Luminus SFT-40 emitter at 5000K and quite high output! It runs one 21700 and has a nice reverse clicky switch.
Official Specs and Features
Here’s a referral link to the Convoy S21G flashlight product page.
Versions
Of the Convoy S21G flashlight titanium, there are two bodies. “Glossy” (seen here) and stonewash. Four CCTs are available (6500K, 5000K, 4000K, and 3000K.) Three emitters are available to meet those various CCTs, too: Luminus SFT-40, Cree XHP50.3 HI, and Cre XHP50.3 HI (High CRI).
Price
The version of Convoy S21G flashlight seen here sells for $53.99. Other options add a bit, up to around $58.
What’s Included
- Convoy S21G flashlight
- Lanyard
Package and Manual
No manual is included. Note that what I have here appears to be the older 8A version. “Driver output current: max 8A buck (old version), constant current, 6a linear driver at present” is how the product page notes this.
Build Quality and Disassembly
The Convoy S21G flashlight is very titanium. I almost always remove the tailcap but either end on this light is quite scratchy (as titanium usually is!).
The threads are nice and beefy, so I don’t have any complaints there, but titanium on titanium is … “bitey.” It’s noticeable.
Both head and tail have nice beefy springs (the beefiest). Both have brass retaining rings, so anything you wish to access on this light is accessible.
Size and Comps
Size: 26mm (body diameter), 27.2mm(head & tail diameter), 126.8mm (length)
Net weight of the flashlight: 123.8g (without packaging, battery, lanyard)
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
A lanyard is included and can be attached through these two holes in the tailcap.
The included lanyard is very basic.
No pocket clip is included.
Power and Runtime
I ran the Convoy S21G flashlight on a single lithium-ion battery – the Samsung 5000mAh 50G 21700. It’s a flat top.
The cell goes into the Convoy S21G flashlight with the button toward the head.
Below are a few runtime tests. I left the light in the default settings, which means the top three levels are 100%, 35%, and 10%.
Check out these temperature graphs. I don’t mention these much because I don’t consider them calibrated or useful, and I scarcely mention the scale that’s shown. The scale starts at room temperature and goes up to 85°C. The Convoy S21G flashlight peaked at around 80°C, which is when I start to get uncomfortable… I shut off one test and let the light cool. In the 100% test, the light will blink on and off. Presumably, this is a temperature control mechanism, but the temp still rises when the light is blinking like this. Regardless of that, the light will be too hot to hold at this point anyway. So be careful.
I’ll point out again that I have the 8A version, and of course, 100% is driven harder. But even on the lower level, the temperature got too hot to hold. Whichever version you have is likely to get very hot. Also the light is titanium, and just doesn’t manage heat well.
This level, unlike the 100% level, did not seem to exhibit the blink warning that the light is very hot.
Modes and Currents
| Mode | Mode Claimed Output (lm) | Claimed Runtime | Measured Lumens | Tailcap Amps |
|---|---|---|---|---|
| 100% | 2000 | – | 1545 (0s) 1186 (30s) |
7.25 |
| 35% | 700 | – | 808 (0s) 781 (30s) |
2.21 |
| 10% | 200 | – | 283 | 0.56 |
| 1% | 20 | – | 32 | 0.07 |
| 0.1% | 2 | – | 6.22 | 0.03 |
Pulse Width Modulation
None of the default levels use PWM.
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’s a single switch on the Convoy S21G flashlight. This is a reverse mechanical clicky. A reverse clicky has the benefit of allowing mode changes while the light is on. But this also means that the switch does nothing until it is on – no momentary action whatsoever.
The action on these metal switches is fantastic. It’s like clicking a good Bic Clic Stic pen – just a rewarding action.
This driver is known as “Biscotti” and has a bunch of mode groups. Actually, this is reportedly not true Biscotti – that’s why I call it “Fauxcotti”. It’s nearly the same though. Mode memory can be turned on or off (yay!), and programming is easy! But there are simply too many possibilities for me to list the UI in a table as I usually do. Here is Simon’s flow chart (the official guide for the Biscotti firmware) for the UI.
From the mode group selection above, the light ships in mode group 1. You’ll want to switch it to mode group 2 quickly of course. 
And I always turn off memory if possible (and it’s possible here!). I made a first pass at my own flow chart, which you can see below.
LED and Beam
My copy of the Convoy S21G flashlight has a Luminus SFT-40 emitter. This is the 5000K version.
The emitter is very accessible; the bezel is not glued down.
Convoy uses a smooth reflector in the S21G.
LED Color Report (CRI and CCT)
On the lower modes, the CCT is within the realm of the 5000K claim. On 100% though, the emitter seems to be pushed very hard and hits over 7000K! Very cool white. CRI is low across the board. (Note there is a high CRI version available, though – a Cree XHP50.3 HI.)
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. The series below clearly shows the bluing on 100% output.
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
I would say the Convoy S21G flashlight is a great candidate for a titanium host to be used in mods. Even if you opt to use this same emitter, you’ll probably want a driver that goes a bit less hard. Certainly a driver that has good thermal management would be the best option. All that said, at around $54, this is a pretty good titanium host. I appreciate that it fits right in with the others like the Convoy T3 – they have very similar designs!
The Big Table
| Convoy S21G Flashlight | |
|---|---|
| Emitter: | Luminus SFT-40 (5000K) |
| Price in USD at publication time: | $53.99 at flashlightgo.com |
| Cell: | 1×21700 |
| Runtime Graphs | |
| LVP? | Yes |
| Switch Type: | Mechanical |
| On-Board Charging? | No |
| Claimed Lumens (lm) | 2000 |
| Measured Lumens (at 30s) | 1186 (59.3% of claim)^ |
| Candela per Lumen | 22.29 |
| Claimed Throw (m) | – |
| Candela (Calculated) in cd (at 30s) | 941lux @ 5.601m = 29520cd |
| Throw (Calculated) (m) | 343.6 |
| Claimed CCT | 5000 |
| Measured CCT Range (K) | 4900-7100 Kelvin |
| Item provided for review by: | Flashlightgo.com |
| All my Convoy 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
- Nice looking host
- Matches other Convoy lights in body design
- High output
- Hits 5000K claim on the lower levels
- Great reverse clicky switch
- Nothing is glued down (modding should be easy in this big host!)
What I don’t like
- Does not hit output claim
- Gets VERY hot
- Low CRI in the Luminus SFT-40
Notes
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