Convoy M21J 21700 Flashlight Review
The Convoy M21J 21700 flashlight has one Luminus SBT90.2 emitter rated to 5700K. It uses a TIR for great throw and has dual switches. Read on for testing!
Official Specs and Features
Here’s a link to the Convoy M21J 21700 flashlight product page on flashlightgo.com.
Versions
Looks like there’s just one version of the Convoy M21J 21700 flashlight. You can buy it with or without cells.
Price
Flashlightgo.com has the Convoy M21J 21700 flashlight for $59.99. Check it out now!
What’s Included
- Convoy M21J 21700 flashlight
- EVE 50E 5000mAh 21700 (2)
- Lanyard
- Contact spacer
Package and Manual
There is no manual.
Build Quality and Disassembly
The build quality of the Convoy M21J 21700 flashlight is very familiar “Convoy.” The light has a great cost-to-value ratio.
This is a “long boi” light – two 21700 cells are required! So there’s no shorty tube.
It’s also not really tactical (not that it claims to be) – the head contact is a brass button.
The tailcap does have a nice big spring, though! (More on that in a bit.)
The build quality, again, is great. It’s possible to disassemble most of the light if you want or need to. That includes removing the bezel!
Size and Comps
Head diameter: 55mm
Battery tube diameter: 28mm
Flashlight length: 223mm
Product weight: 274g
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
There’s a lanyard included. That lanyard attaches to these two holes in the tailcap.
It’s a very simple lanyard.
Power and Runtime
The Convoy M21J 21700 flashlight uses two 21700 cells. Two are required – there’s no short tube for running one cell on the M21J.
Most 21700 cells are flat top, including the EVE 50E’s included from FlashlightGo.com. Because they’re flat top, they don’t make contact together in series. So Convoy includes this neat little contact spacer.
The spacer just goes between the two cells.
Below is how the cells look without the contact. It doesn’t matter if they’re long enough to make contact to the head and tail – they don’t make contact in the middle!
Below is how the cells look with the contact spacer in place.
Here are a few runtime tests. On the turbo test, I did shut off the the light after a number of minutes because the heat was getting high.
Even on the 35% output test, the heat gets so high that you’ll not be able to hold the light. So this is a sort of academic exercise. It would not be smart to turn the light on and put it down (maybe I’m not smart for testing it). On the flip side, the Convoy M21J 21700 flashlight holds over 1500 lumens for over an hour (albeit while getting very hot!). So pick your poison on this one.
Charging
The Convoy M21J 21700 flashlight does not offer charging! I’ll choose this spot to mention you should absolutely make sure that the cells are balanced. Do not use mismatched cells in the Convoy M21J 21700 flashlight. You should use married cells!
Modes and Currents
| Mode | Mode Claimed Output (lm) | Claimed Runtime | Measured Lumens | Tailcap Amps @8.4V |
|---|---|---|---|---|
| 100% | 5000 | – | 3426 (0s) 3214 (30s) |
8.59 |
| 35% | 1750 | – | 1941 (0s) 1892 (30s) |
2.89 |
| 10% | 500 | – | 594 | 0.67 |
| 1% | 50 | – | 66 | 0.10 |
Pulse Width Modulation
None of the modes 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 are two switches on the Convoy M21J 21700 flashlight. First is the mechanical tail switch. With this switch off, there is no parasitic drain at all.
The switch cover sits below the tailcap surround, so tailstanding is possible. It’s a head-heavy light though, so tailstanding isn’t the most secure way to use the light.
The second switch is this e-switch near the head. Bear in mind that on 100% or 35%, the light gets VERY hot and it’s hard to manipulate this switch when the light is hot.
Here’s a user interface table!
| State | Action | Result |
|---|---|---|
| Off | Click tail switch | On (memory) |
| On | Click tail switch | Off |
| Off | Click e-switch | No change |
| On | Click e-switch | Mode advance |
| On | Double click | Strobe |
| Strobe | Click | Previous mode |
LED and Beam
The Convoy M21J 21700 flashlight uses a Luminus SBT90.2 emitter and it’s rated for 5700K.
There’s a big TIR and that produces a nice tight beam and long throw.
LED Color Report (CRI and CCT)
The claim of 5700K is met, with the peak being around 5700K. Duv is positive, which means the beam might be a touch green, and the CRI is low.
Beamshots
These beamshots always have 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. These photos are taken around 18 inches from the door.
I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!
Summary and Conclusion
I love the Convoy M21J 21700 flashlight as a simple thrower made for enthusiasts. Because the temperature seems unregulated on the highest two modes, again, I’d call this a flashlight for enthusiasts. But most Convoys are!
The Big Table
| Convoy M21J 21700 flashlight | |
|---|---|
| Emitter: | Luminus SBT90.2 |
| Price in USD at publication time: | $59.99 |
| Cell: | 2×21700 |
| Runtime Graphs | |
| LVP? | Yes |
| Switch Type: | Both |
| Quiescent Current (mA): | – |
| On-Board Charging? | Yes |
| Charge Port Type: | – |
| Charge Graph | |
| Power off Charge Port | – |
| Claimed Lumens (lm) | 5000 |
| Measured Lumens (at 30s) | 3214 (64.3% of claim)^ |
| Candela per Lumen | 51.6 |
| Claimed Throw (m) | 784 |
| Candela (Calculated) in cd (at 30s) | 3480lux @ 6.728m = 157526cd |
| Throw (Calculated) (m) | 793.8 (101.3% of claim)^ |
| Claimed CCT | 5700 |
| Measured CCT Range (K) | 5100-5700 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
- Great throw
- High output
- Dual switch interface
- Very simple interface
What I don’t like
- Low CRI
- Gets very hot at 100% and 35%
- Positive Duv
Notes
- This content originally appeared at zeroair.org. Please visit there for the best experience!
- Please use my Amazon.com referral link to help support zeroair.org!
- Please support me on Patreon! I deeply appreciate your support!