Total internal reflection (TIR) for Convoy S2+

Looking to make my CONVOY S2+ as floody as possible. To be used as a back up bike light.
Suggestions to what and where I can find a diffuser lens or a simple drop in TIR?
thank you

after some searching I think I found it <?>
https://www.aliexpress.com/item/1577614278.html?gps-id=pcStoreJustForYou&scm=1007.23125.137358.0&scm_id=1007.23125.137358.0&scm-url=1007.23125.137358.0&pvid=bd704f48-e1c2-42c1-ac41-499b69b495d0&\_t=gps-id:pcStoreJustForYou,scm-url:1007.23125.137358.0,pvid:bd704f48-e1c2-42c1-ac41-499b69b495d0,tpp_buckets:668%232846%238113%231998&pdp_ext_f={"sku_id"%3A"12000017900567263"%2C"sceneId"%3A"13125"}&pdp_npi=2%40dis!CAD!3.73!3.73!!!!!%40210323b216693047355026332e1a56!12000017900567263!rec&spm=a2g0o.store_pc_home.smartJustForYou_2002109571628.16

Those are for XML, but if you use other LEDs: Convoy also has optics for 3535 LEDs such as SST20, 519A etc. Using the XML optics on these LEDs means you will need to use a spacer to move the optic a bit away from the MCPCB otherwise you get a darker section in the middle. I tried that with the FC11 and SC31pro, in which I placed a SST20 and 519A. As there is no movable pill in those lamps the spacer required to get rid of the dark middle section meant I needed more space than available so XML optics are not optimal at all for those lamps with those LEDs, so I got 3535 optics from 2021 optics store (also on Aliexpress) and Convoy which work well.

You can find Carclo TIRs for both XM- and XP- size LEDs at LED Supply.

https://www.ledsupply.com/20mm-carclo-led-optics

Select LED compatibility and other specifications.

Do these ones have an opening for xp or xm LEDs?

The S2+ is not exactly a thrower.

This may or may not be useful because the specifics I don’t know what emitter you are using, and what I bought two years ago on Fasttech can’t be found there anymore even though I have the packing slip with the item numbers and SKUs. But anyway, I made an order of four different wider 20mm TIRs to replace one of the two spot TIRs in my Yinding bike light style headlamp (with two XM-L2), looking to blend the beams with one spot and one wider beam.

They included (in pack of 5s except 25-degree was a single):

- item no. 110.8200, 91189/Cree 30 degree Ang+

- item no. 114.4800, 91532/20mm 30-degree Opt+

- item no. 965.2420, 44678/19.5 25-degree O+

  • item no. 965.2421, 90652/19.5mm 45-degree O+

One of the 30-degree optics was matt/frosted with a built-in spacer at the emitter end, the other 30-degree optic had small beads no spacer, the 45-degree had large beads no spacer, and the 25-degree had a smooth front and short spacer feet on the emitter end. I ended up putting in the 45-degree optic in the Yinding and that in combination with the spot TIR in the Yinding blended great for trail running/cycling. Then that light finally died.

I’ve been trail running with my YLP Gekko 1.0 headlamp since a bit after my Yinding died. It had a nice wide beam that was good indoors and seeing my feet when running, but didn’t give enough punch to see ahead far on the trail. A couple weeks ago, I was shopping new headlamps for running, until I finally remembered about the optics I had sitting in a box. It turns out the Gekko also uses 20mm optics. In fact, the optic in the Gekko was 100% identical to the beaded 45-degree in the Fasttech order. I ended up comparing five optics in the Gekko, the four listed above, as well as a spot from the dead Yinding (the style where you can feel a small nub in the front of the optic). The Gekko has a LH351D.

My favorite was the 30-degree with the small beads, which looks like the “25-degree” beaded optic in that Convoy link. It gave a good punch out the front while sacrificing some peripheral light, but still enough to see where my feet are going while pointed up the trail. The other 30-degree, the matt/frosted front one, was substantially weaker in overall output - seemed to have much greater losses, but maybe it was just diffused to the sides?. I didn’t notice any darker sections in the middle with any of the optics, but the Gekko supports the optic behind the wide end of the optic rather than against the board.

That got me thinking of my S2+ with SST-20 2700K. I had added some no-see-through window film under the lens when I got it because I hate hotspots in the traditional reflector type beams. It weakened the throw substantially but made it usable for me. After the success with the Gekko, I put another 30-degree small beaded optic in the S2, and it also looked great, much better than the reflector+window film in output and beam shape. Since that optic doesn’t have a spacer built into the bottom, I put the spacer that came under the reflector in the light under the optic, though it seemed kind of insecure. After a run bouncing the S2 around in my pocket, that spacer came loose and was making a racket in the head. I removed the spacer and tried the optic against the board directly. Turns out the beam is still perfect with no dark sections at all (even though the optic is maybe Cree style?). Held at handlebar height, I’d say it produces a great, rideable beam too. (side note: I left off the flat glass lens front that came with the S2+ and am running the TIR “unprotected” because I think TIRs don’t need protection.)

L-R: spot, 25, 30 with small beads, 30 with matt/frosted front, 45
S2+ and Gekko both with 30-degree small-beaded optic

!!

Thanks for all the input.
When I get the TIR and film I’ll post some pictures.

The frosted TIR work well in the S2, I never liked the clear TIR in that light with any emitter. You will have to sand the tab off the lens if you order the ones from LED Supply, but it is very quick. The opening size is not really labeled well on the site, I wish they would just list the opening.

You could also just sand lens that came with your S2+. I’ve done that numerous times and you can vary the beam diffusion by using different sandpaper grit. I’ve only sanded the inside of the lens, but you could sand both to get it even more floody.

Here’s an example of 1 of my sanded (frosted) lenses:

You can get 20mm TIR lenses in anything from 5° through 120° or wider.

I don’t go past 60°, because 90s and 120s tend to have artifacts in the beam, specifically eerie rings.

Took out the optic and replaced the lens with the film from a broken LED monitor. Sorry for the messy hobby room.



1 Thank

Simon sells an 85 for 3535, you lose a lot of perceived power because it’s so floody. It’s basically only useful up to a couple of meters, to the point that it’s actually kind of annoying how short the throw is. I use an 85 in my Boruit D10 headlamp, only for closeup work like soldering and cooking.

It's true and it'd be nice if it was simply labeled. However, I think they made a tweak to the web page as I was able to more easily sort for the wanted LED profile. I can send them an email and request that they provide a better description.

I remember loneoceans made a design before with a honeycomb reflector in S2+

this is the link from his website: Essays with TIR lenses on Convoy S2+: XML2 + XPL-HI [Update]

The two room pictures are before and after images?

What about 120° beaded?

Ain’t got, so dunno.

Beaded might get rid of artifacts, but can’t say for sure.

[quote=Lumaine Moore]

Yes. Was trying to show how floody the light got. I can do some outdoors shots if that would help.