Convoy s21b Camping Hiking
Max current output is 6000mA
Its biggest advantage is that no frequency can be seen in any mode, and there is temperature management.
It can control the flashlight temperature not to exceed 55 degrees Celsius,
If the flashlight temperature is below 55 degrees Celsius, it will output full current. If it is above 55 degrees Celsius, it will constantly adjust the current so that the flashlight will not overheat.
Convoy S21B and S2+ Review
I ordered these lights at the beginning of the month but they took forever to arrive.
Convoy s21b The package came from China but actually landed in the US within 4 days. However, at that point, the carrier messed up and routed it to Utah, Nevada, back to CA, then bounce around in CA for a few days before arriving at my door. Sigh…
Anyway, what matters is they’re finally here.
I originally wanted a Convoy S2+ with the high powered SST40 emitter (1800 lumens vs 1000 on a typical S2+) so I can add my brass 18350 battery tube to it. However, when it arrived, I found that the thread on the new S2+’s are different now so the brass tube doesn’t fit. Doh!
I also wanted a 21700 version so I ordered the S21A (2300 lumens). However, just after I ordered, I learned about a new Convoy flashlight called the S21B. I contacted Simon (manufacturer of all Convoy lights) to switch to the new light. He did it and threw in 2 lighted tail cap switches to boot.
I love the S21B but the S2+ (at 1800 lumens) is no slouch. Both are very bright.
This is with 2x 5500 lumen LED shop lights in the background so the beams are much brighter than this picture.
On max, the head on both lights warm up within 40 seconds.
The S21B’s black aluminum body feels like it’s rubber coated but it’s just matte anodized aluminum. Very different design from S2+. The stainless steel bezel is a nice touch although I wish it was a bit larger to create more of a contrast against the rest of the body.
Pretty close in size. Convoy s21b on top accepts 21700 battery (also 18650) while the S2+ takes 18650.
That gap between tail cap and battery tube bothers me a bit, but that’s my OCD talking
Both are SST40 5000K so they look very similar. This emitter is a bit green on lower power but they’re bright white on high or max.
The 2 new lights flanking my current favorite Convoy light: Sand S2+ with 18350 brass tube. I modded the S2+’ s tail switch to a blue lighted switch then changed it to orange. This is on 20% remaining battery so it’s dim. Here’s a pic of it on fresh battery vs S21B (which will get the blue button treatment soon)
Modding options and thoughts
The driver design of the Convoy S12 lends itself to only simple modding – the easiest way to push more brightness out of this light is to send more current down it. The R010 resistor on the driver board can have another resistor in parallel to increase the 100% amperage; to increase it from 6A to 7.2A, an R050 can be laid on top and soldered down. The size of these resistors is 2010 (or 5025, metric), though I have had success with 2512 due to scarcity of 2010-sized low-value resistors. Some common resistances will add the following if put in parallel.
Convoy s21b Emitter swaps should be relatively straightforward too – 3535 footprint.
Perhaps the craziest thing that I’m going to attempt is making this a UV monster – Emitter swapping with some SST-10 365nm emitters, and replacing the AR glass with a ZWB2 filter. Now, the glass on this is around 30.5×2.5mm, and I’ve found a 30x2mm on AliExpress, or 29×1.5mm on KaiDomain – It won’t be perfect, but at least pretty close. I’d also probably do a resistor swap to R015 to limit it to 4A – while the SST10 in djozz’s tests indicates that 2A should be no problem, I’m not prepared to take that risk just yet.
Comparison shot shows from left to right: FW3A with Nichia 219B sw45k, S12 219C 4000K, and FW3A XPL HI 5000K (it doesn’t look anywhere near that green to the eye!)
Measurements were taken both indoors and outdoors with the Uni-T UT383S. I took three measurements at both 5m for indoors and 10m for outdoors, and so as to account for any variance in my aim, I’ve averaged the results. Given that this light is a multi-emitter light, I’ve set the lux meter to “max” mode, and waved the light gently around to let all of the hotspot hit the sensor, so as to capture the brightest point.
As seen in the runtime graph, running on the highest mode only gives a short amount at full blast before thermal throttling kicks in, and when it does, it kicks in hard. Just before the three minute mark, my light dropped rapidly to very close to 38% relative brightness, and sat there for a very long time (around 84 minutes).
I can’t then explain the rest of the graph, as this was in a room with the door closed and no external light – although I suspect that the last section is where the voltage dropped below the LVP mark, and then bounced back up after a while, sufficient to “reignite” the light as it were, before finally dropping again.
Convoy s21b – HOME PAGE