Convoy S12 UV Review – Simple UV Excellence?


The Boring Stuff

I purchased this light with my own money from Convoy’s official Aliexpress store. It’s available with a ZWB2 filter preinstalled for most of the world. If you’re in the US you have to order the listing with a clear lens, then also purchase the ZWB2 filter and install it yourself (super easy). Below are the official specs.

What comes in the box?

The box is one of Convoy’s old-style thin white cardboard ones. It’s got flaps on the end that open and the light is inside, wrapped in bubblewrap, with a lanyard preinstalled. That’s it. A sturdier box would be nice but this is adequate.

Size & Measurements

Fireflies E07x Pro | Convoy S12 | Convoy M1 | Emisar D4V2 | Noctigon KR1

MeasurementMeasured (mm)
Bezel Diameter34.5
Maximum Head Diameter34.5
Switch Boot Diameter16.3
Lens Diameter30.8
Lens Thickness2.5
Body Tube Diameter (internal) 21.9
Body Tube Diameter (maximum)27
Pocket Cip Slot Width (on body tube)2.5
Pocket Clip Slot Diameter26.35
Driver Diameter22

Weight: 198g / 7.0 oz with Molicel P42A battery & Noctigon KR1 pocket clip

User Interface

The UI is very simple.

OffClickOn (mode memory)
OnHalf-pressCycle mode (low-high-low-etc)

I understand why Simon chose to go with a super simple UI here, because most users won’t need more than one or two modes in a UV light. I would have preferred him to include a 12-group driver and have it ship in a simple mode group so that more advanced users can pick the mode group they want and enable/disable mode memory as they please.

I installed this 22mm 12-Group driver in mine. The hardware is identical, this just comes with the 12-group firmware so I get access to some other modes (like battery check) and the ability to disable mode memory.

Runtime & Currents

Disclaimer: It’s hard to measure a UV light, so I put a GITD diffuser inside my runtime box and pointed the light at it to generate visible light that my phone could pick up. I used the lux measurements from my phone in the ceilingbounce app to generate these “measurements” and graphs.

Performance: The light heats up a fair bit on 100% mode, and thermal regulation causes stepdowns. When the brightness jumps back up in the runtime graph, that’s because I turned on a fan to help keep the light cool. It was getting concerningly hot, so hot that I could barely touch it even for a split second.

LVP: I don’t know if there is LVP but these UV LED’s have such a high VF that you probably can’t over-discharge the batteries even if you tried.

Driver & Regulation

S12 UV uses one of Convoy’s 22mm 6A linear drivers, but it comes with a special 2-mode firmware. Ostensibly it should deliver 6A to the LED’s, but due to their high VF it can only manage up to 2.4A with a fully charged battery.

Regulation is poor. That’s to be expected when driving UV LED’s from a single Li-ion cell with a linear driver. It would have been cool to see a ~3A ~4V boost driver here to regulate power, but that would have increased cost substantially.

Note: All regulation measurements are taken at turn-on so they do not reflect any thermal or low voltage stepdowns that may occur.

Thermal regulation: is present, but the light still got concerningly hot. This seems to be common in Convoy lights, based on my testing.

Emitter & Beam

S12 UV uses three Seoul CUN66A1G emitters in a triple reflector and behind a ZWB2 filter. The filter blocks all visible light coming from the emitters so you only get UV.

The beam is nice. It’s a good balance between throw and flood so you can make stuff glow from a distance but you also can make everything in front of you glow too. Since it’s a triple reflector the beam isn’t perfectly symmetrical. The spill is a little bit triangular and has six flower petals around the outside. The hotspot and corona are pretty even though. It’s hard to get on camera. In actual use you notice none of this because you’re just seeing random stuff glow. It’s a good beam profile for being able to catch stuff glowing in your peripheral vision and then you can point the light at it to make it glow brighter.

Here are a bunch of random photos I took while playing with the light.

Design & Construction

S12 is a well designed host and I think it’s a great choice for a high output UV light like this. The triple emitters give you extra brightness and flood. The cooling fins on the head help it run longer on high mode.

The bezel is stainless steel and it sits in front of a glass ZWB2 filter. The reflector is held in place by an o-ring and I was able to remove it by tapping the head on a hard surface a few times.

Build quality is good. The threads for the body tube are high quality, lightly lubed, and square cut. They’re anodized on the tailcap end so mechanical lockout works. The threads for the bezel aren’t as nice. They are finer, dry, and a little gritty, but you don’t need to unscrew it often (or ever). Overall the machining is great, anodizing is pretty good, and there aren’t any issues.


The switch is a reverse clicky mechanical tailswitch covered by a rubber boot and it works fine.

I prefer a forward clicky personally so that’s what I installed in mine. If you want to do the same thing, you’ll need some snap ring pliers to take the tailcap apart. Buy these switches and solder one on the tailcap PCB in place of the original reverse clicky switch. Then cut the little nub off the inside of the switch boot with a sharp knife and reassemble. Convoy’s 20mm rubber and metal lighted switches work just fine in S12 UV too if those interest you.

Carry & Ergonomics

S12 fits nicely in hand without any issues. I find a reverse grip the most comfortable and it allows me to actuate the switch with my thumb. A forward grip is quite comfortable as well thanks to the length of the light and the flats milled into the head, but you can’t turn it on/off with one hand in this grip. A cigar grip works great too and the flats on the head make nice thumb rests. There aren’t any hotspots or rough edges, but it can get pretty toasty if you’re running it on high mode for a few minutes.

No pocket clip is included, but the universal screw-on clip should work fine if you want to carry it. S12 is similar in size to the Noctigon KR1 & Fireflies E07x and they fit in my pocket well enough. S12 does have a mechanical switch that’s less prone to accidental activation than those other two lights, which would be nice if you decided to carry it. I’m sure it’s hard to notice a UV light that’s accidentally turned on in your pocket.

Update: after initially posting my review, I found that Noctigon KR1/KR4 clips fit S12 UV like a glove. To install, you just have to temporarily remove the o-ring on the same end of the body tube where you want the clip to go, and then put the ring back once you’ve installed the clip. The shallow carry version (pictured) will fit bezel-up with no modification whatsoever. Both the shallow carry version & deep carry version will fit bezel-down, but you’ll need a piece of solid core 20AWG wire to act as a conductive spacer in the tailcap.

Batteries & Charging

S12 runs on a single 21700 battery. I did all my testing with an unprotected flat top Molicel P42A. I also tested with an unprotected flat top Samsung 30Q and a protected button top Xtar 21700. Both worked fine, but the 30Q did have some side-to-side rattle if I shook the light. The springs on the driver and tailcap are long and beefy so it can accept a wide variety of cells.


Here are some lights in the same class as S12 UV and how they compare.

Convoy S2+ UV: cheaper, smaller, 1×18650, not as bright, doesn’t come with ZWB2 filter by default, single mode, can be shipped into the US, numerous body color options

Emisar D4V2/Noctigon KR4 UV Mule: smaller, more expensive, substantially brighter, much more advanced UI (Anduril), ZWB2 filter preinstalled, can be shipped into the US, magnetic tailcap, multiple body color and material options


S12 UV is is a bright and floody UV light that’s not too expensive. It’s well made and my only complaint is the poor regulation, but that would require a much fancier (and pricier) driver to fix. I can’t think of a better high-powered UV light for the price and I highly recommend it.

2 thoughts on “Convoy S12 UV Review – Simple UV Excellence?

  1. Thank you for the review. I am trying to buy this in the USA, but can’t seem to find it without the filter installed. Do you have any recommendations? Aliexpress only has it with filter installed. Obviously can’t buy it with the filter installed. Appreciate your advice!


    1. Unfortunately you cannot buy S12 UV in the US because it’s only sold with the filter installed. I had to buy mine through a group buy where a foreign user purchased several, shipped them to a guy in the US, and then he shipped them to all the buyers. I don’t think there are any group buys going on currently.


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