MOD: Shortened blue Convoy S2+

Here’s a recent mod I did to a Convoy S2+. The host is one of the blue Convoys with the beautiful metal clicky switch. I’ve had this laying around for awhile, but finally decided to do something with it.

I performed the following mods to this light:

  • Installed DrJones H17F driver and triple XPL HI 5A2 on copper Noctigon
  • Carclo 10507 Optic
  • Significantly reduced overall length of the light.

Overview and pictures:

Step 1: Shorten the pill. I used the same technique I used in a previous mod. Here are some pictures (taken from an earlier S2+ mod using the same technique):

Shortening the pill requires the following steps:

  • Grind off the back of the pill I used a grinding bit and a hand drill, then filed it flat. If you’re patient you can accomplish this step using just a handfile.
  • Use a handfile to remove the forward section of threads near where the emitter sits. The S2+’s head isn’t fully threaded so this is necessary to allow the pill to seat further forward. You can see on the picture above how the sides of the pill below the emitters are smooth. This is because I ground off the threads.
  • Grind out new ledge for the driver in the sides of the back pill. To do this I placed the pill upside down in a vise. Then I bent a small piece of aluminum into a “U” shape with a flat bottom. and placed it upside down in side the pill. I cut away the legs of the “U” till it sat just a few mm inside the pill. Then I used a cylindrical grinding bit in a hand drill with no grinding edge on the bottom to grind the edge of the pill. The “U” acted as a stand to prevent the grinding bit from slipping further in.

Step 2: Install the driver and emitters. I chose a DrJones H17F for this build and triple XPL-HI 5A2 on copper Noctigon. Due to the nice brass pill, it was possible to solder the driver in for an excellent ground connection.

Step 3: Shorten the head. With a dramatically shorter pill, the light was usable as-is with the 18350 tube, but with an 18500 inside. However, I’ve already done that before and wanted to make this an 18650 light. With the much reduced pill, the battery compartment is much too large for an 18650 cell. I considered sawing the battery tube in half and using the “human lathe” method to shorten the battery tube. But then I realized there was a much easier way to shorten this light:

  • I took a hacksaw and sawed a large chunk of the back of the head off. Since the pill threads and the battery tube threads are the same, this worked well. I then filed it flat.
  • The threads on the battery tube were hitting the back of the pill so I used a handfile to remove approximate 2 mm of threads. There’s still more than enough threads left for a strong fit.
  • I used the same technique described in Step 1 for grinding out a driver ledge in the back of the driver to grind out the bottom couple mm of threads in the head. This allows the head to fully seat and still be o-ring sealed. this operation was the hardest part of the mod. I messed up the first time and had to take a little more off than I anticipated when the grinding bit slipped. Fortunately, for anyone else trying it, this step is also purely optional. It’s only needed if you want a waterproof light and don’t want to glue the head to the body tube.

NOTE: the stand that I made to hold the grinding bit at the right height for this operation was a bit more complex than the “U” described previously. For this operation I cut 2 disks of sheet copper sized to the inside of the light. Then made a rectangle from a strip of copper and placed it upright between the 2 copper disks. I soldered all 3 pieces of copper together to make a secure stand that would sit inside the head while I used the drill bit. I did the grinding with the pill removed.

The result: a much more pocket-friendly 1x18650 Convoy. Entire light is now just 102mm long, compared to 118mm for the stock light. A full 16mm was removed. It is now definitely one of the shortest 1x18650 tube lights with a clicky tailcap switch! Here are some more pictures:

I am quite pleased with the performance of this light and really like how it came out. I limited the turbo output to 3 amps as I found that on FET modes the head got far too hot given the tiny head and lack of heatsink fins. Since the heatsinking isn’t good enough to hotrod for max output, I’ll probably skip adding a wire bypass to the tailcap spring.

Overall, this mod wasn’t really all that hard to do. I give it an intermediate level of difficulty. Well worth a try for anyone with basic modding experience who wants an extremely short tailcap clicky tube light.

Still to do on this light:

  • Lighted tailcap - I have some on order, and I hear with this driver, they should slot right in with no need to install any resistors. Should illuminate the white rubber ring around the metal tailcap clicky.
  • Possible anodizing removal - I saw the beautiful polished S2+ someone had in the “What did you mod today?” thread. Also, I started filing the inside of the tailcap before I realized it wasn’t necessary. That’s why the inner edge of the tailcap near the battery tube shows bare aluminum.
  • Open up a couple mm inside the battery tube - currently the light only fits unprotected flat tops. I originally had a bit more room inside the light, but the grinding bit slipped when I was carving out the threads at the head to make way for the o-ring and I had to take off a bit extra at the head. I should be able to makeup this extra space by filing down the copper post at the back of the driver and the top of the tailcap retaining ring.

Cool, thanks for showing :THUMBS-UP:

Very cute!

Pretty cool mod. I am looking forward to the details on the lighted switch mod.


Actually, my plan is just to swap the regular clicky for lighted tailcap switch . I’m hoping I can just swap it in.

I’ve tried one of those, seems to make the light next mode memory by itself.
That was on a MTN Fet driver and X2R.

I recall reading sometime last week that someone had tried one of these with an H17F and it sill worked perfectly. Guess I’ll find out when it arrives.

Hope it does, would save some muckin around.
Let us know.

That’s what I am most interested in.


Now this is what I call modding. :beer:

I like making things smaller. :slight_smile:

I have a blue host waiting for action too, but i noticed that ring (which i think is nylon) is not as translucent as i hoped it would be…
But i couldn’t get it out, but i think a more translucent replacement / alternative ring will help a lot.

Oooh! I’m gonna need to try something like this.

Can it be shortened to say 110mm without grinding the head threads?

Whst did you do to the tailcap?

Hi Firelight, sent you a PM. Thanks.

I need to do a search on the S1 18350 version modded to take a 18500 .. I just got Two blue 18350 versions in the mail today cheap off amazon .My 18350's are pretty old and I have too many 18500's unused just layin about.

For mine I cut the front off the brass pill and replaced that with some sheet copper totaling 2.5 mm thickness. Short springs, thinner brass button spacer(.5mm) with trimmed rubber cylinder, just the optic and no lens, 101.3mm wih 16650 2.5Ahr cell.

Do you mean 18650 ?
I would really like to see some pics of yours too !
BTW, nice work OP ! THAT is modding :smiley:

Nope, I mean 16650. It’s a 4.35V Sanyo cell purchased from RMM. Now that it’s done I should really update that thread. The 16650 is used since a brass sleeve is needed both to carry current through an otherwise wood tube and for strength. Since the brass fits inside the threaded tube ends it reduces available ID in some cases requiring the use of a narrower cell. K&S Precision metals makes some great thin wall brass tubing but only thicker walled stock in this diameter. I can now make my own thin wall tubing but it’s not so precise. I’ve also reamed this same tubing enough for an 18650 but it still requires the narrowest of cells. I really enjoy seeing how others do mods like the one in this thread and what different approaches to shared obstacles are used. The length of threading in the heads of S2’s is what makes the mod here possible and fuels the imagination for other mods as well.

The new short head also works with the 18350 tube with an 18350 cell inside.

However, note the gap between the head and the tube. This is because I didn’t file off the threads on the 18350 tube as much as I did on the threads on the 18650 tube. This gap wouldn’t have been there if I hadn’t accidentally slipped with the grinding bit and ended up having to shorten the head a little more than I first intended. Also, in retrospect I don’t think I should have tried to shorten the tailcap at all. If I were doing this mod again I’d fix those problems so there were no visible gaps.

As-is, I might be able to fix the gaps on the current sample, but to do so I’d need to open up a little more room inside the battery tube. I should be able to get 2mm from filing down the top of the switch retaining ring and contact post on the bottom of the driver. But to get more than that I’d have to grind the pill flatter.

Here are some pics of the light with 18350 tube (it is fully functional with either length tube):

That’s awesome. With the new pics you can really appreciate how short you made it.

Very cool mod. Thanks for sharing.