Thinking of doing a Convoy S11 Quad as my first build...

In thinking of what I’d like in a flashlight, pleasant tint and high sustainable output seemed important. Sure, turbo on my FW3A and EDC18 are great, but they last less than a minute at that brightness. Sure, my Sofirn SP33 can hold about 1000 lumens without overheating, but that XHP50.2 is just so ugly, and it doesn’t ramp.

I have been looking on mtnelectronics, and thought I’d try to make my own light. Thinking of using a Convoy S11 host, four Samsung LH351D leds (deciding between 4000K and 5000K), and their FET + 7135 driver running Crescendo firmware. I was planning on using a copper spacer they sell for the Convoy S2. Between it and the quad optic behind the lens, it should hopefully use up enough space to replace the reflector. I’m not positive it will though. Of course I’d still have to drill a hole through the center of the pill too…

Besides the spacer concern, all in the parts (including some solder I need and thermal compound) cost around $65. Also of concern, this is my first build and I’m not confident in my soldering skills. And then, knowing me, I’d consider the 26650 size too big and want to build a similar triple light using an S2, which would cost close to the same price to build. In the long run, that’s not too much money, but I do already own the three lights mentioned above, along with four S2+s and a C8, two Fenix 18650s and two 16340s, two Sofirn 18650s, myriad AA/14500 and AAA lights, a bunch of usb charging keychain lights, and the obligatory Maglite ML300L 3D (in all, over forty flashlights).

So I will end this post with these questions:
Do I really need more lights?
Am I just bored because of the current home-bound environment?
Do I know enough to build a light properly?
Will I have already bought all the parts by the time you read this??

So…Some help (eventually :smiley: ):

Is that a real question in this world? :stuck_out_tongue:

Probably, and start learning to mod/build some lights is a nice way to escape boredom :wink:

That I don’t know, but I do know one thing: you can do it!!
You’ll need to start somewhere, you’ll need the tools, the materials, the skills, but you don’t get it from nothing!
So, at least, order your stuff, start practising and you’ll be able to do it :wink:
Or do you think that all the modders around here were born like they are now? :student:

Well, that depends on your decision, your wallet and the shipping companies :smiley: But, I do hope you already got all the stuff because now you won’t have any excuse that stops you from start modding!! :partying_face:


Here’s some help:
Threads asking for the S11 Quad:

Proper spacer for the quad: Low-cost copper pills, spacers, optics, drop-ins (Updated 23/10/2022)) - #1661 by MascaratumB

The S11 quad is on my horizon! That is a beast of a light!!! Even if it gets hot on a quad, it will eventually hold a little more than the other lights you mentioned (S2+, FW3A). It is bigger, thicker and surely can take some beats too in case you use it as a work / walking light and drop it more!

It is surely an expensive mod, but remember that you’ll have a light that will last you…“forever” if you do it right!

Some specific things:
Driver: If the light takes a larger driver see if MTN has the same firmware in those drivers and avoid using the driver spacer.

Firmware/User Interface: About Crescendo, a while ago I did a video with using a light with that FW. You can see it here: Driver giveaway: Constant current 17mm drivers, winners (finally) announced, post #2. - #150 by MascaratumB See it it suits you or if you prefer another type of user interface!

Soldering skills: They come with practice, with a good soldering iron and a good solder wire too! Start practicing in other things you may have laying around so that you learn before you “really” mod the light you want. I am still looking for the perfect conditions as an amateur modder…


Hey, I am not a good modder, I startd with the same fears you have, and I still have many of them! But I’ll leave you some sort of inspiration:

This is the quad light I made for the Old Lumens Contest 2019. I was also fearing some of the same stuff, but it ended up well and it is now a light that I will keep for life!

You do your quad S11 and you’ll see you won’t regret :wink:

Good work and tell us what you’ll do :+1:

I would go for it! Part of the fun of building and modifying flashlights is that you can make them according to your own specifications. One of a kinds that you can’t buy anywhere.

MascaratumB posted some good info/links and it appears the S2 spacer should work, but it seems you already know that.

And assuming this goes well, you may also want to modify some of your existing flashlights like swapping out LEDs, bypassing springs, adding lighted tailcaps, etc.

Thanks for the great advice and enthusiasm! I came very close to clicking on that “complete order” button…

But I psyched myself out when I thought of the Emisar D4SV2… which is pretty much exactly what I want, with an side e-switch instead of a tail forward clicky, and with Anduril, and less expensive than buying all the parts for a build. If I really wanted the LH351Ds, that’d be an easier swap than building a whole flashlight, and would then cost about the same. It’d be an easier introduction to modding as well.

But I’m not giving up on building a light just yet. I like the M2 host, as that could dissipate heat fairly well with those fins and still use 18650s. I also could start with a simple S2+ triple. I thought that instead of using a spacer, what about an 18500 tube to shorten it.

So I’ve chickened out for now, but the desire is still there. I still hate soldering and am not very good at it, even though I’ve done it (with much frustration) for r/c cars. If I ever do pull the trigger, I’ll be sure to take pictures of the build and post them!

I did an M2 mod last year. An excellent host. Mine has quad Nichia 4000K LEDs (beautiful tint!) and an ice blue lighted tailcap. Here are some pics to maybe get you thinking about it.

I think Richard at MTN has MCPCB’s that fit that D4Sv2 and I know he sells LH351’s. He will even flow them onto the board for you. If all your wanting to do is change up your D4S that is a fairly straight forward job.

Might want to drop him a email about the MCPCB though. I am not completely sure if the ones he sells will fit. I think I got my board from Int Outdoor when I did my emitter swap on a D4S.

Stick with the proper spacer on the S2+ build. You’ll be happy you did. That S2+ will get as hot as any other tube light when you start feeding it the brightness. They are great host for getting your feet wet though.

I did it! I ordered all I should need for a Convoy S11 Quad with LH351D 4000k LEDs. It was expensive, but coming from Mountain Electronics, at least I know shipping shouldn’t take too long.

The decision came after having to file a Paypal claim against a Sofirn order whose tracking number information has not changed in six weeks. The money refunded from that order will take care of about half of the cost for this. I hope I bought the right spacer, and I hope it all goes together well!

I guess it’s a little too early to heat up the soldering iron…

Nice :wink:
Keep us updated of your mod !
I’m sure you’ll succeed :+1:

Thanks! I’ll try to remember to take pictures.

I am a little confused about my order from Mountain Electronics though. After I clicked checkout and Paypal sent the payment, I was brought back to the site’s checkout button. I didn’t press it again, but it did not remove the items from my shopping cart. Fortunately, the order showed up in the “Order History” section. Strangely, it says the order was completed. …What happened to processing and then shipped? Is this normal for Mountain? It’s my first order from there.

Boy, that wasn’t a good start…

All my stuff arrived today for the build. Looking in the box, as I removed the MCPCB from its little bag, it slipped out of my hand and fell right into the crevice in the couch between the springs and the arm rest. It took me over a half-hour with the couch upside-down to fish the damn thing out. I even broke a spatula trying to wedge something thin enough down there to get it. But get it I did, fortunately. I hope I didn’t damage any of the domes on the LEDs. I will get some pictures taken of all the parts before I start the build.

Well, I took pictures while I did the build yesterday evening, but I forgot that BLF requires some link to an outside image website, and I don’t have any accounts like that (nor do I feel like making one). Oh well.

But I did learn a few things putting this light together.

1. Do NOT hold the pill with your bare hand by the threads while drilling a hole through it. The drill bit caught and the pill spun in my hand. The threads cut my thumb. It’s not a bad cut (only about a quarter inch slice, and it barely bled), but it sure was a dumb one.

2. Do not try to stretch out the spring with the positive wire attached to it AFTER it is soldered to the board, especially if you are bad at soldering.

3. Being liberal with thermal compound leads to a messy flashlight build.

Seriously though, it went together well enough, even though I am terrible at soldering. The 4000k LH351Ds give a nice tint, and the light puts out a minimum of a couple of lumens, up to what seems to be a maximum around 3000 lumens. It can maintain maximum brightness for several minutes as well (except for when my first soldering attempt came loose from heat after about thirty seconds).

The spacer was just a touch too short, leaving the flashlight prone to mode switches when shaken as the battery lost contact with the springs. Fortunately, the Convoy host came with its own spring to be attached to the board. I had Mountain Electronics put one on, so I simply screwed the extra on onto the tail spring. No more battery rattle!

The light is VERY floody. There is no hotspot nor is there any spill; the light is just a uniform disc of large diameter. It’s very pretty, though almost too much flood; I’m concerned it won’t have enough throw for outdoor use on moderate power. I ordered the carclo lens that was said to have the most throw. Either the others are absurdly floody or I was sent the wrong TIR lens.

Crescendo is an interesting firmware which would be much more intuitive and user-friendly with a reverse-clicky switch instead of a forward. As I learn it and the half/full press sequences to perform different tasks, I am still getting incorrect mode activations. I’m still fiddling to see if I like having the memory on or off.

Overall I am happy with the flashlight, though it does bother me that I could have bought an Emisar D4Sv2 with XP-L HI 5Ds and anduril for less money. But I will say that Mountain Electronics did a great job reflowing the LEDs to the board, and sells some great stuff.

Nice job and thanks for your report. I had a chuckle at your description of the few things you learned. :smiley: These flashlights can be pretty fiddly to put together, but you tend to learn the important stuff pretty quick.

The LH351D is a relatively large LED so tends to make the beam large. The TIRs also tend to make a larger beam with less spill, but that doesn’t necessarily mean the beam won’t be intense. The TIRs do a good job of making wide and intense beams, so I think it will work for you. However, you are right that combo of 4 LH351D in the small reflectors makes for a relatively less intense beam partly because each LED is only seeing a quarter of the total current so it’s more difficult to drive each LED hard enough for good throw.

I, too, like Crescendo. It’s definitely better with a reverse clicky. I’m curious, when you have memory on, does it go directly to the memorized mode when you turn it on or does it start in moonlight mode for a fraction of second before going to the memorized mode? I’m using a very early version of Crescendo which has that feature, but I don’t know if it was kept.

Thanks! If I ever build another light, I hope those things aren’t repeated… like the old rule of shutting off the circuit before changing a light switch. I know it’s the right thing to do, but I’ll electrocute myself a few times every time I do it.

Yes, the light will turn on at the floor for a second before switching to its memorized brightness. My FW3A does that too, yet my EDC18 does not; I guess that was an update to anduril. It’s not too intrusive though. The most annoying thing I find is that sometimes, even though memory is on, it starts to ramp when I first turn the light on. Sometimes from the floor, and other times from the memorized level. My guess is it’s something weird with the memory from how I turned it off with the forward switch. Like, to stop ramping requires a quick full click off and then a full click on. If I don’t turn the light back on right away, it seems to resume ramping the next time I turn it on. Accessing the shortcuts requires half-presses and then a final full click. Sometimes it memorizes the floor or ceiling shortcuts. If I do a quick off-on, it’ll ramp up, unless I accessed turbo directly. Then it switches to moonlight. Maybe I’m just an idiot…

I think it’s worth getting a reverse clicky switch. See here for one that will work:

Sorry to hear that your S11 didn’t go as well as you planned. I’ve never had a pill cut my fingers while drilling a center hole, but will keep that in mind in the future. There always seems to be some type of challenge when building your own flashlight, but that’s just part of modding. Regardless, congrats on your first mod!

What happened was I drilled a 3/8” hole first and decided I wanted it a little larger. When using a 1/4” bit, it caught on the edge of the already drilled hole, cocked a bit sideways and got wedged, and spun the pill in my hand. Whoopsie doodle!

I’m mostly happy with the build, and getting used to using the forward switch. I may eventually look into a reverse clicky, but whomever tightened the retaining ring on the host made it really tight… I couldn’t easily get it off. So I’ll live with it for now. I’m actually really coming to enjoy its floodiness. I tend to use it at a higher level than I might a different light, but that’s o.k.

I’m here to request pix

You don’t need accounts for this


Hey, that worked! Thanks for the link!!


On the left is my FW3A with XP-L HI 5000K on its lowest.
On the right is my S11 Quad on its lowest (LH351D 4000K).

You can see that the S11 is brighter on low, but also look at how much larger its beam is. The lights are a little less than a foot from the wall.