Convoy has released a new 26650 light.  It’s a medium thrower, but with the addition of built-in charging and a side e-switch.  Looks pretty solid on paper; read on to see how it tests!

Official Specs and Features

Here’s a link to the official product page.  That’s the official Convoy page.


There’s only one body, and only one emitter available, but it’s available in four emitter temperatures: 6500K, 5000K, 4000K (seen here), and 3000K.

Price and Coupon

This light is $27.99 at BangGood.  That’s an affiliate link – click it just for good times!  That doesn’t affect your price but does keep the reviews coming!

Short Review

Solid build, good specs and built-in charging.  Seems like a winner at $28!

Long Review

The Big Table

Convoy M4U
Emitter: Cree XP-L HI (4000K)
Price in USD at publication time: $27.99
Cell: 1×26650
Turbo Runtime High Runtime
LVP? ?
Switch Type: Mechanical Side Switch
Quiescent Current (A): ?
On-Board Charging? Yes
Power off Charge Port with no Cell? Lowest 4 modes. With cell, all modes.
Claimed Lumens (lm) 1000
Measured Lumens (at 30s) 764 (76.4% of claim)*
Claimed Throw (m)
Candela (Calculated) in cd (at 30s) 1367lux @ 5.77m = 45511cd
Throw (Calculated) (m) 426.7
All my Convoy reviews!
  • Measurement disclaimer:  I am an amateur flashlight reviewer.  I don’t have $10,000 or even $1,000 worth of testing equipment.  I test output and such in PVC tubes!!  Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).

What’s Included

  • Convoy M4U Flashlight
  • Two o-ring 26650 to 18650 adapters
  • Lanyard (attached)

Package and Manual

The light ships in a slip-fit cardboard box.  The label on the side indicates the temperature, but not the model number (???)

There is no manual, but the product page gives this UI description.

Build Quality and Disassembly

Typical good Convoy build quality.

The switch is easy to access.


There are adequate fins in the head for cooling.

The knurling is plentiful and also not aggressive.

The bezel has crenelations.

The cell tube is not reversible.  The threads are not even the same size, so it’s not possible to flip it accidentally.  The anodized end is the tail end.

The driver is held in place by a brass retaining ring.  Since this is a side mechanical switch, it’s also held in place by the bezel on the switch.  And charge port.  There’s really a lot going on here.

The tail end has a big soft spring.

These tailcap threads are big and beefy, anodized, well lubed, and square cut.  This means locking the light out takes only breaking the contact between the tailcap and body.  (The same can’t be said for the head end.)  Also see that o-ring below?  It’s pushed up too high on my light.  Because of that, when twisting on the tailcap, I eventually wore that o-ring out and it broke.  So keep it lower than what you see here, or you’ll cut yours too.

The bezel comes off easily, revealing the reflector et al.

There’s an emitter centering ring.

And of course, the emitter is very easy to get to at this point.

Size and Comps

Head diameter 41.3mm
Body diameter 33.2mm
Length 142mm
Flashlight weight 60g

Retention and Carry

The only way intended for carry of the M4U is the included, and attached, lanyard.  It’s a fine, uncomplicated lanyard.

I’ve said this before about Convoy and I’ll say it again – I feel like this is not the right way to connect this lanyard.  There are two holes here – use them.  Attaching it this way (below) means that the light doesn’t tailstand as smoothly.  It’s not a big deal though, and easy to change.

There are no pocked clip attachment points, no magnets, no pouches etc.  The lanyard is all.

Power and Runtime

The M4U is a single cell light.  It’s meant for a single 26650, and with springs on head and tail, any type will work.

Also included are these two o-ring adapters, which allow flawless use of 18650 cells.

Here are a couple of runtimes.  The highest mode (not officially called Turbo, but “100%”).  Output is more or less stable for almost an hour, then trails off toward the low voltage cutoff, of over 3V.

Regarding the highest output being a good bit lower than spec – that could be due to a number of things.  Possibly this light needs a high drain cell and the cell I tested with wasn’t pushing enough current (unlikely, but possible.)  It seems the light only pulls around 2.3A on 100%, so the cell shouldn’t really matter.

High (again not “High” officially but “35%”) looks about the same but lasts much longer.  Again, the cutoff is over 3V.

The M4U has built-in charging.  This happens via micro-USB, and there’s a little indicating emitter in that hole beside the port.  When charging, the light is red.  The port cover is a good one.  It presses in very securely.

Charging proceeds at around 1A (just over, in fact).  This means the charge rate is good (perfect) for 26650s, and quick for 18650s.  Either is safe to charge here.

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
100% 100% 764 2.37
35% 35% 322 1.07
10% 10% 72 0.25
1% 1% 12 0.04
0.1% 0.1% ~ 0.01

Pulse Width Modulation

There’s PWM on all modes but the highest.  I don’t notice it though, so you will probably not either.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  And here’s the worst PWM light I have ever owned.  Also one of the very first lights I ordered directly from China!

User Interface and Operation

There’s a single switch on the M4U.  It’s a mechanical switch, and it’s in the head.  There is no tailswitch on this light – just the uncommon side mechanical switch here!

If you glance at that switch and what you see is the standard metal switch from the Convoy S2+, then I’d say you’re probably right – the switch cover is almost certainly identical.  But likely the covers are the same.  This version is a much squishier version, and has a centering ring.  There is no backlight though.

Here’s the standard Biscotti flowchart.

Here’s a UI table!

State Action Result
Off Click Low (if no Mode Memory disabled (default)), Next Mode (if MM enabled)
On Click Off
On Tap Mode advance
On Long tap (>0.5s) Reset to Low (if no MM), No action (if MM enabled)
On Tap >10x Configuration Mode*
  • Configuration mode allows a few things to be changed.  Once configuration has been entered, the light will stop responding to repeated taps.  Stop tapping, and the light will flash once, then “buzz” (very fast, low strobe).  Click during this strobe to enter group selection.  (Clicking the light completely off will work, as will tapping, in every case I’ve tested.)  Once in group selection, the light will blink for mode group numbers.  Click (or tap) the light after the count of the group you want, and you’ve set the group.  Ie if you want group 3, wait til the light blinks one blink, then pauses, blinks twice, pauses, blinks three times, and click during this pause.

If no click is made during the first buzz, the light will flash twice, then buzz again.  Click during this to iterate mode memory (on or off).

LED and Beam

The emitter of choice here is a Cree XP-L HI, and mine’s 4000K.  There are three other temps; one warmer (3000K) and two cooler (5000K, 6500K).  But 4000K is best K.

The reflector is deep and very smooth.

Below hilights the travel of the switch.  Again, I find it a bit squishy but it’s not bad.

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure.

Tint vs BLF-348 (Killzone 219b version)

Test light is on the left.

I compare everything to the Killzone 219b BLF-348, because it’s inexpensive and has the best tint!


What I like

  • Good throw
  • Nice build quality
  • Good charging

What I don’t like

  • Killed the o-ring – maybe the groove for it isn’t developed enough
  • Didn’t hit 1000 lumens as claimed (thought that isn’t necessarily a light fault)


  • This light was provided by BangGood for review. I was not paid to write this review.
  • This content originally appeared at  Please visit there for the best experience!
  • Shop my store for the best lights!
  • Whether or not I have a coupon for this light, I do have a bunch of coupons!!  Have a look at my spreadsheet for BangGood and GearBest coupons. Please subscribe and get notifications when the sheet is edited!!

1 thought on “Convoy M4U Flashlight Testing”

  1. I would say it doesn’t hit the 1000 lumen claim because you’re testing the 4000K version, warmer tints are always less. The 6500K would be a lot closer. This should of been mentioned. It has nothing to doing with the battery

Leave a Reply

%d bloggers like this: