The new Convoy S21A (with SST-40 LED) can be found on the manufacturer’s website HERE. It is similar in size/appearance to the Convoy S2+, but is slightly larger, due to the larger 21700 battery. Information about the SST-40 LED (6,500K) can be found HERE, (thanks to BLF member djozz).
This review will include:
(1) lumens measurements
(2) runtime graphs
(3) temperature readings
(4) PWM test
(5) beam pattern/tint
Manufacturer spec for high is "up to 2,300 lumens".
The S21A has only four brightness levels, which according to the manufacturer is because;
“is very suitable for ordinary users”
Using my Texas Ace Calibrated Lumens Tube:
Level 4 (100%) 1,770 lumens (0 sec) – 1,635 lumens (30 sec)
Level 3 (30%) – 695 lumens (0 sec) – 675 lumens (30 sec)
Level 2 (3%) – 82 lumens
Level 1 (.1%) - 0 lumens (could not measure)
Framed by two S2+ for size comparison.
Framed by two S2+ (front view).
Framed by two S2+ (back view).
The S21A comes with an orange peel reflector.
High (no cooling)
High (with COOLING)
Level 3 (30%)
Level 2 (3%)
As seen in the "high" runtime graphs, the S21A starts throttling down immediately, to control heat. According to the Convoy website;
Temperature readings taken with a Fluke 62 Max Plus IR Thermometer.
As you can see, the temperature gets HOT rather quickly. After fifteen minutes, the light was too hot for me to hold.
If the Crescendo user interface becomes optional (which has a thermal setting), it may solve this issue.
NONE was measurable (at any brightness level) using an OSRAM BPW34S PIN photodiode and an oscilloscope. This confirms the manufacturer claim “no frequency can be seen in any mode”
The SST-40 LED tint is noticeably green at level two (82 lumens), but is not as noticeable on level 3 and 4. This greenish tint was also noticed on the Convoy S11 (which also uses the SST-40).
The orange peel reflector helps smooth out the center beam.
Conclusions so far:
This light has the potential to be as popular as the S2+. Unfortunately, it suffers from a few things I don’t like.
- The brightness level spacing is very wide. There are only four brightness levels from .1 to 100%. For example, there is no brightness level between 80 and 600 lumens. A more customizable UI would be nice, similar to Biscotti. While the design goal was "is very suitable for ordinary users", it may leave flashaholics a bit disappointed. However, again, Simon has hinted at the future availability of the Crescendo user interface. Edit update - there is now a twelve mode version available HERE
- The greenish tint from the SST-40 LED is rather noticeable, especially at lower levels (82 lumens).
- Temperature management could use some user control. Most people will not be able to hold this light for long on high. High should be considered as a turbo mode only. If the Crescendo user interface is released (which has a thermal setting), it may solve this issue. I do not personally like my lights to get too hot. All my S2+ lights have only three chips (7135), which keeps them warm only. Of course, this is all a matter of opinion/preference.