Convoy S21E Flashlight Review

The S21E is one of Convoy’s few e-switch flashlights! Offering many emitter choices as well as USB-C charging, it’s a great low-cost option!

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Official Specs and Features

Here’s a link to the Convoy S21E flashlight product page.

Versions

There’s only one body, but you can get multiple emitter options. There’s Luminus SST-40, Luminus SFT-40, and Nichia 519a.  The CCT available ranges from 6500K (cool) to 2700K (warm), and each emitter is not available in each CCT. The Nichia option gets an orange peel reflector while the other two have smooth.

Price

At Ailexpress, this version of the Convoy S21E flashlight sells for under $20.  That’s a fairly ridiculously great price for this light!

While this Nichia 519a model seems to be out of stock at NealsGadgets, there are a couple of versions of Luminus options available there. Have a look; stock looks to be changing frequently (referral link to NealsGadgets).

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Short Review

For twenty bucks it’s very hard to go wrong with the Convoy S21E flashlight.  Even if you buy this light simply as a 21700 cell charger, you’re getting a pretty good deal! Add in that you could try your desired flavor of emitter and you have a fantastic deal.

Long Review

The Big Table

Convoy S21E Flashlight
Emitter:	Nichia 519A (4000K)
Price in USD at publication time:	$19.67
Cell:	1×21700
Turbo Runtime Graph	High Runtime Graph
LVP?	Yes
Switch Type:	E-Switch
Quiescent Current (mA):	0.03
On-Board Charging?	Yes
Charge Port Type:	USB-C
Charge Graph
Power off Charge Port	With cell: all modes Without cell (and/or tailcap): all modes (but actual output depends on your power supply)
Claimed Lumens (lm)	1300
Measured Lumens (at 30s)	1063 (81.8% of claim)^
Candela per Lumen	11.83
Claimed Throw (m)	–
Candela (Calculated) in cd (at 30s)	550lux @ 4.81m = 12725cd
Throw (Calculated) (m)	225.6
Claimed CCT	4000
Measured CCT Range (K)	4000-4300 Kelvin
Item provided for review by:	Nealsgadgets
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’s Included

• Convoy S21E flashlight
• Lanyard (attached)
• Pocket clip (attached)

Package and Manual

I didn’t receive a manual with the Convoy S21E flashlight.

Build Quality and Disassembly

The Convoy S21E flashlight punches so far above the $20 price that it’s quite ridiculous. At $20, I’d say you should buy multiple so that you can test whatever emitter interests you.

The tailcap has a nice big beefy spring!

Same on the head, but with a different spring. Both springs are very robust.  The head and tail end of the cell tube are not the same – unanodized thread go on the head end.

Size and Comps

Size: 27.3mm (diameter), 116.4mm (length)
Net weight of the flashlight: 88g (without packaging, batteries, headlight straps, and holding clips)
Product gross weight: 98g

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.

Also above is 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.

Retention and Carry

The Convoy S21E flashlight ships with two means of carry. Both are attached from the factory. First is this lanyard, which attaches on the tail end.

This is an improvement over previous Convoy lights (in my opinion!) because the placement of the lanyard doesn’t interfere with tailstanding.

Next up is the pocket clip, which attaches on the tail end, too. This is a two-way friction-fit clip.

Clip hug!

Power and Runtime

The Convoy S21E flashlight runs on a single 21700 cell.

Since there are springs on both the head and tail, the cell options are pretty great. I think any type of 21700 should work. I’ve tested exclusively with a flat top Vapcell 21700 that can provide a rated 30A, and should be perfectly sufficient for this light. There’s not any spare room along the diameter of the cell though, so if you have a particularly wide cell, then you could have a problem. Actual 21mm cells should be just fine though.

Charging

Convoy has put USB-C charging on the S21E.  The charge port is on the head and opposite to the switch.

Charging works with both USB-A and USB-C power. No cable is provided.

C to C looks about like the A to C chart above. Both are very good!

While the Convoy S21E flashlight is charging, the switch indicates in red. When charging is complete, the switch turns green. These are both very bright and I’d be pleased to see the brightness taken down to 1/4 or so of the current state.

Modes and Currents

From here to the end, I’ve mentioned five modes. I set the light to the stepped option (ships in ramping by default). In the stepped option there are four modes. But if you hold the switch when the light is off, you’ll get a lower low. Thus, technically 5 modes in stepped. I’ll add that the difference in “moon” and “low” (mode 1 and 2) is very minimal.

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps
5	1300 (probably for the cooler CCT’s of Nichia 519a)	–	1063	6.39
4	–	–	467	1.85
3	–	–	178	0.60
2	–	–	15	0.04
1	–	–	~	0.02

Pulse Width Modulation

None of the modes have PWM. The wave on those higher three modes below – not PWM. Also not something you’ll notice.

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

Convoy uses an e-switch on the S21E. The E really stands for “e-switch” in the name, I think. As a comparison, the Convoy S21A is a mechanical switch flashlight very similar to the S21E.

While this switch is “fine,” I think that future versions of this light will probably see better switch covers. This switch cover doesn’t feel very refined. It has high edges and is quite large.

All that said, it’s a fine switch as far as functionality goes.

This e-switch offers ramping (by default) but if you’re like me, you’ll switch to the stepped output levels right away. There are (in a manner of speaking) a few mode groups… however it could also be said that each of the options for output exists under the main (or single) group of ramping. I’ll try to convey this information completely in the (one) table below.

Here’s a user interface table!

State	Action	Result
Off (Ramping or 4-mode)	Hold	Moonlight (0.2% output, 0.01A)
Off (Ramping or 4-mode)	Click	On to memorized mode
On (Ramping) but not in Moon	Hold	Ramp Up (or down, depending on previous ramp direction) to highest (or lowest) and blink once^
On (Ramping or 4-mode)	Click	Off
Any (Ramping or 4-mode)	Click 2x	Turbo (100% output)
Any (Ramping or 4-mode)	Click 3x	Strobe^^
Off (Ramping or 4-mode)	Click 4x	Tactical Mode (100% only, Momentary only)
Tactical Mode	Click 4x	Previous state (Ramping or 4-mode)
Off (any group)	Click 5x	Voltage detection: Emitter blinks the ones, then pauses and blinks the tenths. So *** then ******* is 3.7V.
Off	Click 6x	Iterate between Ramping and 4-mode
On (4-Mode)	Hold	Output increase (1%,10%, 40%, 100%)
Off (Ramping or 4-mode)	Click 10x	Iterate lockout.
Lockout	Click	Emitter blinks in once in low output
Moon	Hold	No action

^ Ramping isn’t cyclical – the ramp stops when it reaches the extreme of that direction. You must release and click/hold again to change directions. It’s possible to stop anywhere along the ramp, and the next click/hold will ramp in the other direction.  It’s not possible to ramp up, then release, and wait a certain amount of time, and click/hold and again ramp up for example.
^^ The product page says the light must be off to access strobe. I find that 3 clicks will get strobe regardless of the current state (on or off).

Note that despite the switch having an indicator function of both red and green, these color indicators are not used for anything regarding the user interface.

The switch can also indicate in orange, but that seems to happen only when the charging port is active with no cell (and/or tailcap). It could also be during runtimes, but I didn’t observe that.

LED and Beam

Convoy offers a few options here, but I went with a Nichia 519a emitter in 4000K.

Because of that emitter choice, I got an orange peel reflector, too. The other two emitters ship with smooth reflectors.

LED Color Report (CRI and CCT)

Just at a glance on this gallery below, you can see how closely that big red circle matches that big black circle. That’s good. That’s what you want. A complete overlap of those two would basically be “perfect” output. Aside from that, we can say that the 4000K is fairly accurate – I’m seeing 4000-4300K, depending on the output level. CRI is also great, at well above 90. Thus, this is a High CRI option on the S21E.

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!

Conclusion

What I like

• Low cost
• Very great CRI and CCT from the 4000K Nichia 519a
• Ramping option
• USB-C charging works great (at over 2A, so “fast charging”)
• C to C charging works, too

What I don’t like

• Cell isn’t included
• Switch indicator is underutilized

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Notes

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