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FyrFly Convoy C8 365nm UV Flashlight - The Next Generation Convoy - an Original Design by Group Cons

Reinventing the Convoy for the Fluorescent Mineral hobby Here's what Eric Rintimaki, Mr. Yooperlite, said about this design (he's selling a copy made in China; hopefully built with the quality of the FyrFly):

"These lights out performed the 4 and 6 watt Convoys! And it wasn't even close! I even have to say that they are brighter and have a longer reach than even my $425 Raymond Wu lamp!!!!!!!This is a game changer for sure!!!!!"

FyrFly Convoy C8

The Design

I got tired of waiting for some flashlight manufacturer or seller to produce a decent, professional Convoy type flashlight. No one has (on a reasonable budget). The Chinese manufacturers are happy to sell (and misrepresent) Convoy flashlights as 4 watt, 5 watt, and even 6 watt lights - they are not. Worse, domestic sellers unwittingly propagate the mistruths.

So - I decided to release my design for a very powerful light, with over 2.7 watt radiant output @365nm (UVA), consuming 8w power from the battery. I posted it on Facebook and a lot of discussion ensued. Engenious Designs, a midwest light manufacturer and major contributor to this design, decided to manufacture the end product we came up with and offer it to the hobby. It was met with immediate success and lots of happy customers. ( Many folks had them at the MW FMS meetup in August and were amazed at the power and throw.

Imitation is the best complement, Chinese manufacturers are starting to sell copycats.

Be very careful when purchasing a light manufactured in China. Ripoffs are rampant, and copies often don't adhere to rigid engineering practices (unspecified LEDs, junk batteries, poor manufacturing quality, improper hearsinking, and more). As time and budget permit I may try to evaluate some of these knockoffs.

Note: There are broad ranging claims that a piece of glass installed in a flashlight is protected by a patent - even the original clear lens supplied with all flashlights falls under the sweeping claims made by this individual. I will not offer my opinion on the validity of this claim. Do your own research. The patent holder publicly states that it is permissible for individuals to install a filter for their own use.

Below is the post I made on FB last June. A lot went into the design of this new light between Rhett and I - we knew there would be others who would copy the design (I posted it publicly) but we hope it will benefit the entire hobby.


It really doesn't cost much more than a run-of-the-mill Convoy in parts, but is DRAMATICALLY more powerful. The pic below shows the parts. They consist of:

  • Convoy C8 host (just a little bigger than a normal Convoy - the gray light shown next to the C8 host to show relative size) ($11)

  • A 1500ma buck driver driven at 7.4v - $5, (w/ the two CR123/16340 rechargeable batteries shown, or optionally two 18650 batteries)

  • An LG 6w LED (same as Convoy)

  • a 44mm (42mm works) ZWB2 filter ($4)

  • Two CR123 batteries (rechargeable ones - higher voltage required)

The standard reflector is smooth (not orange peel). I prefer it as has much better throw and reflectivity. The head of the light is much larger - needed for the heat generated by the LED. This light will run as long as the charge of the lithium batteries holds (about 45 minutes) - with no degradation of power output (unlike today's Convoys). (Note: as with all LED flashlights, it is preferable to allow the light to cool periodically. The head gets hot; allowing it to cool will extend the life of the LED. Momentary operation preferred). The beam power, intensity, throw are all simply amazing. No comparison to the Convoys being offered today. You'll want to carry spare batteries.

Convoy C8 Parts View

Not hard to build as long as you know how to solder an LED and are somewhat dexterous (tight corners). If this is Greek to you, don't bother - does require some tech skills. I may post a DIY page on this and another light I am working on in the near future. But can't teach people how to do it here on FB - just want to get this info out there for the DIY folks. It's a worthy build - trust me!

Adding a few more facts after discussion:

  • This light requires (2) rechargeable CR123 batteries. The non-rechargeable ones only put out 3.0v and rapidly decline from there. Under 6.0v the driver on this light flashes the LED to indicate a discharged battery.

  • Runtime will be about 35-45 minutes on a set of batteries. There is ZERO degradation of light output over this time.

  • The light gets very hot after ten minutes on time. After 30 minutes the head is so hot you cannot hold it; the body only a little less hot. Intermittent/momentary use is highly advised. Just turn it on when looking, off when not. Don't make the mistake of putting it in your pocket when on.

  • I have tested the beam out to 80' (feet), lighting up a piece of sodalite. I posted a couple of videos showing this.

Another option is to add an extension tube to allow the use of two each 18650 batteries in this host: - the resulting light will be longer which some may not like, but the runtime vastly improved.

Beam Shots

Took a couple of quickie beam shots (6' away from the target). Two different exposures to try and capture the "essence" of the beams. Keep in mind that 1.5A is the rated current of this LED. Anything above that is a gamble. The Convoy is one that was sold as "6-watts" and has a fully charged battery running at 4.15V. The 3A beam on the right, and the Convoy on the left are both using orange peel reflectors. The other two are smooth. There is a minor difference between smooth and OP. These lights can be driven at higher currents but that exceeds the manufacturer's specifications.

Test of the new "FyrFly" Convoy C8 flashlight, comparing it to a "6 watt Convoy".

(Hint: there's no comparison!)

I took two videos of each flashlight. Both lights had newly charged batteries and I aimed them at a UVA meter, adjusted for maximum output in each video. The meter measures mW/cm2. The Convoy started out at 46.7mw while the FyrFly started out at 74.4mw. I ran them for 30 minutes while taking a stop action video, and I crunched the video time down to 15 seconds. (Convoy on the right, FyrFly on the left).

After 30 minutes both lights were too hot to hold. The Convoy had dimmed to 22.5 (54% decrease in brightness) while the FyrFly only dimmed to 63.8 (16% decrease in brightness). The dimming in the Convoy is due to two things: battery discharge and heat. The dimming in the FyrFly is due to heat only; battery discharge does not affect it. As our LEDs heat they lose power - nothing can be done about that (except not to use it for 30 minutes continuous on time). But the failing of the Convoy is that it cannot maintain full output as the battery discharges (at the end of this test, the 18650 battery was only discharged to ~3.5v).

The FyrFly is a dramatic improvement on an already excellent flashlight - the Convoy Reinvented.

Some unsolicited comments from folks on Facebook

Chance F. I heartily commend you folks on this approach..the throw on this bad boy is phenomenal and in the mines I've ventured into it has light weight and portability and doesn't heat up too bad and batteries last a good while.. Much kudos to all who contributed..its killer and worth my money. This beast is the real deal 365nm has durability.. lots of throw with just how much it'll make a specimen react..and reach will amaze you on the distance it can produce effective hunting in the field..wide path of light that I can safely walk in among brush and doesn't get hot in your hands and it has a nice amount of time of use compared to my other true LW'll be very satisfied brother..

Philip N. I discovered why Rhett Peterson‘s new offerring is called the FyrFly...sure attracted the bugs at Minerva (much more so than the was great in spite of the unpleasant biology)

I received the Convoy C8 "Firefly" flashlight from Mark Cole that Rhett Peterson plans to sell. I'm very pleased with the performance so far. Using a programmable power supply, I ran a test of input voltage versus current draw to characterize the module. Voltage was measured at the head and the head was "pre-heated" to a typical operating temperature by running it for 10 minutes first. It maintained a very consistent 7.5 watt draw from 8.3 Volts down to 5.6 Volts, with current draw increasing as voltage dropped. At 5.5 Volts, the light shut down and would not come back on until voltage was removed and then re-applied with at least 5.8 Volts. Thisis good, because it shouldn't draw voltage on the rechargeable 16340 Li-ion cells down to an unsafe level - assuming the cells are pretty well matched. As soon as the light shuts down or blinks due to low voltage, the cells should be removed from the light to prevent a small parasitic current from further depleting and damaging the cells over a prolonged period of time.

— feeling happy.

Bob T. Holy cow, this light is insanely bright. Thanks Rhett! ps: and thanks Mark Cole

Don C. I got mine yesterday(Sat.8/3) the battery charger is a quick charger(about 1.5hr charge time) the light is very much brighter than the S2.The "spot" is much larger. Heat buildup is minimal. Now to try battery life. So far, I am very pleased with this light!!

Richard B. Hi Rhett, have the torch, came Wednesday. Have used it in my shed and elsewhere, have to say most impressed!!

(From Reddit): "Well, I got one. It's twice as intense as a standard uv convoy s2, with a substantially larger hot spot and at least twice the usable working distance. Fluorescence is brighter. In particular, minerals that are dim with an s2 show way more of their color. Phosphorescence is correspondingly more intense as well. Feels the same as an s2 in the hand. If you don't have something like an s2 yet, and you were considering one, and you've got the budget, this c8 is very much better."

Yooperlites These lights out performed the 4 and 6 watt Convoys! And it wasn't even close! I even have to say that they are brighter and have a longer reach than even my $425 Raymond Wu lamp!!!!!!! This is a game changer for sure!!!!!

I heartily commend you folks on this approach..the throw on this bad boy is phenomenal and in the mines I've ventured into it has light weight and portability and doesn't heat up too bad and batteries last a good while.. Much kudos to all who contributed..its killer and worth my money


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