Convoy S11 GT-FC40 Flashlight Review

The Convoy S11 GT-FC40 flashlight is a 26650 tube-style light, most importantly with the GT-FC40 emitter! Read on for thoughts and testing.

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Official Specs and Features

Here’s a link to the official Convoy S11 GT-FC40 flashlight page.

Versions

This is a Convoy flashlight, so I’ll go out on a limb and suggest that there are 100 versions of the S11 specifically.  Of “this” version (which I’m saying very non-specifically) there are basically three.  The body colors are Black, Gray (seen here), and Silver.  This S11 has the GT-FC40 emitter, but there are two versions available:  4000K-4500K (seen here), and 5000K-5500K.

Price

This Convoy S11 GT-FC40 flashlight weighs in at a reasonable $27.53.  To the best of my knowledge, this is the least expensive complete flashlight with the GT-FC40 (which is precisely why I bought it).

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Short Review

As I hinted above, I mostly bought this light to test this neat GT-FC40 emitter.  There are other less expensive ways to get this emitter, but not without modding.  There’s an mcpcb and driver for the Convoy L6, but…  what better reason to buy a new flashlight than this?  So this review is sort of two parts.  First the emitter:  yes, it’s great, buy it.  Second the Convoy S11.  It’s fine.  The fit and finish only get an “ok” from me, and 26650 tube lights are not tiny, but at this price, I consider this to be a good value.

Long Review of the Convoy S11 GT-FC40 Flashlight

The Big Table

Convoy S11 GT-FC40 Flashlight
Emitter:	GT-FC40 (4000K-4500K)
Price in USD at publication time:	$27.53
Cell:	1×26650
Turbo Runtime Graph	High Runtime Graph
LVP?	Yes
Switch Type:	Mechanical
On-Board Charging?	No
Claimed Lumens (lm)	–
Measured Lumens (at 30s)	1644
Candela per Lumen	9.7
Claimed Throw (m)	265
Candela (Calculated) in cd (at 30s)	680lux @ 4.963m = 16749cd
Throw (Calculated) (m)	258.8 (97.7% of claim)^
Claimed CCT	4000-4500
Measured CCT Range (K)	4500-4700 Kelvin
Item provided for review by:	Me
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 S11 GT-FC40 Flashlight
• Lanyard (attached)
• 26650 to 18650 o-ring bumpers

Package and Manual

The Convoy S11 GT-FC40 flashlight ships in a bubble wrap baggie.  There is no manual.

Convoy S11 GT-FC40 Flashlight Build Quality and Disassembly

You can probably notice right away my first issue with the build quality of the S11 – the head is different color anodization than the body.  That’s “fairly minor” but still annoying.

Here’s ye olde top-down view:

I’ve used this light a bit since I got it (and maybe some before I took the photos) – so I can’t necessarily blame all the little dents and dings on Convoy.  But there are some hard edges all over the light that just have little dings.  Nothing worse than the light will get from a few days worth of use, and not even anything like a drop would cause.  Just here and there, dings in the edges and the like.

The tailcap comes off easily to reveal anodized, square-cut threads.  These threads are long(ish) and since they’re anodized allow mechanical lockout with just a gentle loosening of the tail.  (Of course, this is a reverse mechanical clicky, so further lockout isn’t really necessary.)

The head threads are unanodized, but otherwise the same as threads on the tail end.

This thread setup does mean the cell tube is reversible.  And while I tried it this way to confirm it does work, the light did not seem to like it, and stopped working this way after one full cycle of modes.  (Which is completely weird, electrically…)

On the tailcap end, there’s a nice big beefy spring.  Just a single though, not double and not bypassed.

The head has just a brass button.  It’s a long button!

Also note this unusual retaining ring setup – there are two!  That inner ring has “normal” threading.  After removal, it looks to have the same diameter as the driver.  The inner retaining ring diameter is 22.74mm, and so I’d call that at 22mm driver, too.  That external “retaining ring” isn’t actually a retaining ring, either.  That’s the pill itself, which unscrews easily.

I will add that the driver seems secured into the pill in some way – with this inner retaining ring removed, the driver is still mostly unwilling to come out.  Also, there’s no leverage, despite the brass button being so appealing to push against…

I will add that the driver seems secured into the pill in some way – with this inner retaining ring removed, the driver is still mostly unwilling to come out.  Also, there’s no leverage, despite the brass button being so appealing to push against…

The head has some not-very-deep cooling fins.

These insets in the fins look like the rails on a Cool Fall Spy 007, which I find interesting.  I believe on that light they are intended for use to mount on something.  I don’t think that would work here.

Size and Comps

• Diameter: 33mm
• Length: 139mm
• Net weight: 167g

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.

And here’s 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 S11 GT-FC40 flashlight has only one means of being carried.  That’s the included lanyard, which ships attached.

It ships attached in the way that frustrates me about all of Convoy’s lights – it ships as seen below.

You’ll want to correct this immediately of course, in the way shown below.

This way is better because it allows tailstanding!  And this light will tailstand fairly well, too.

These lanyard holes are only on one side.

There is no pocket clip or pouch or anything else included for carry.

Power and Runtime

Amazingly, the Convoy S11 runs on a single lithium-ion cell.  The cell tube is suitable for a single 26650, but Convoy includes the bumper o-rings seen below for using a single 18650, too.

Why is “single-cell” amazing here?  Because the emitter being used in the light is a 12V emitter, and so the driver must boost that ~4V from the cell to 12V!  So for under $28, you get a fancy boost driver, a fancy new GT-FC40 emitter, and even a host to hold it all together.  Pretty great.

The cell is installed into the light in the usual way – positive end toward the head.

The 18650 fits very well with the bumpers, too.  The only downside to this is that the cell doesn’t contact the metal body at all, so heat management won’t be quite as good.  And as you’ll see later, on turbo (or “100%”) this light really draws some heavy current!

Output on turbo starts at around 1800 lumens and falls off, down to the next mode, which is “35%.”  Toward the end of the run, you can see what the light exhibits as low voltage warning, and the finally shutting off.

The next highest mode is around 700 lumens, for almost 2 hours.  I don’t think we’re setting any efficiency records here, but it’s a very pleasant 700 lumens!

Modes and Currents

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps
100%	100%	–	1644	~9.30
35%	35%	–	716	2.37
10%	10%	–	222	0.64
1%	1%	–	18	0.07
0.1%	0.1%	–	6	0.02

While the driver is pulling 10A or whatever from the light, the emitter is only seeing around 3A or so.  Some very rough, rounded math:  10A*4V = 40W.  40W/12V=3.3A.  The driver boosts the 4V to 12V by taking “more current” than you might expect for a power of around 40W.  And at the emitter side of things, that 40W is no longer 4V, it’s 12V, so the current is lower at around 3A (allowing some inefficiencies).

Pulse Width Modulation

No PWM on any of the 5 selected modes (0.1%, 1%, 10%, 35%, 100%).

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

Used here on the Convoy S11 GT-FC40 flashlight is a reverse clicky mechanical switch.  Surrounded by this big body, it may look small, but it’s a completely normal-sized switch and switch cover.

The switch is not proud and doesn’t prevent or interfere with tailstanding at all.  It’s accessible from two sides very easily, too.

A reverse clicky has the benefit of allowing mode changes while the light is on.  But this also means that the switch does nothing until it is on – no momentary action whatsoever.

This driver seems like “almost Biscotti” but not exactly quite Biscotti.  Still, much of it is very much the same.  Mode memory can be turned on or off (yay!), and programming is easy!  But there are simply too many possibilities for me to list the UI in a table as I usually do. Here is Simon’s flow chart for Biscotti.

From the mode group selection above, the light ships in mode group 1.  You’ll want to switch it to mode group 2 quickly of course.    And I always turn off memory if possible (and it’s possible here!).  I made a first pass at my own flow chart, which you can see below.

I think the only thing missing from actual Biscotti is that entering programming requires 20 taps instead of just 10.  Either way, tap til the light stops responding!

LED and Beam

The emitter here in the Convoy S11 is a GT-FC40.  It’s an interesting emitter, and fairly new…

This emitter only exists in a 12V format (as far as I know), and so lights that will work with it are somewhat unusual.  There’s a version of some Cree XHP emitters that have a 12V operation, but often flashlight companies will use the 6V version instead of the 12V, so even swapping this into other lights that have same-footprint mcpcbs isn’t always a given.

Anyway, the emitter I chose with my purchase is a “4000K-4500K” version.  The documents state this as a “high color rendering LED” but I don’t see the CRI stated specifically (just “above 90 CRI”).

It’s a very, very great output!

The reflector is deep and lightly textured.

Based on the image below, it looks like the lens has AR coating, too.

Since the bezel is smooth, no light escapes when headstanding.

LED Color Report (CRI and CCT)

The CCT here is a pleasant 4500K-4700K, with very good color rendering (CRI of ~95, aka “High CRI).

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

• Use of GT-FC40 emitter!
• 4000K-4500K option
• High CRI
• Versatile user interface
• Includes 18650 adapter
• No PWM
• Low cost

What I don’t like

• I accept the size, but it doesn’t fit any good roles, being a 26650 tube light…
• Looks like the host (the S11 itself) has taken just a bit of abuse before it got to me
• Head anodization doesn’t match the rest of the body

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Notes

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