I’ve read somewhere that a TPAD + carclo quad optic can be used if diameter on the optic is reduced. However, from what I can tell, the height of the set up differs from stock?
Has anyone successfully rebuilt this with carclo optics? I’m on the fence on this light and this could be a deciding factor.
I have built an S41 with Tpad quad and fitted Carclo. Used XP-L HI 3A and it works great with MtnE Fet+1 on Bistro.
However I have Not tried it with the new designed heads they are now using. Optic is now supported in the copper head, not the legs of the optic as a Carclo would be.
Sounds like quite the pocket rocket. I’d be interested in doing something similar with 4x 219C.
How did you reduce the diameter of the optic? and did you notice any fitment issues? The original s41 optic and board has a different height than a tpad + carclo.
I’ve used these Nichia 219CT 4000K R9050 with the Mtn. Fet+1 Bistro and I don’t think it could get any better… at least for my skill levels.
Edit: Plus I never did buy the complete light, I waited until the heads got straightened out and bought the heads only with using my points at BG the cost was $27 and $4 per LED, used all A6 no ano tubes and Astro tubes for the rest, always thought the SS tubes and switch would be just to heavy for my liking and it worked out great, especially the no ano A6 tubes all buffed up shiny, looks real good.
Has anyone noticed a difference in heat dissipation between the stainless and aluminum versions?
I’m not saying that the BLF-A6 driver is a bad driver for the S41, just that it is not especially made for it and could use tweaks. I like it better than any other driver they could have chosen.
That one got the Tpad soldered directly to the copper head using a hot plate. Carclo was filed by hand. You can trace the original optic on top of the Carclo to know when to stop filing. It is 2mm reduction which is 1mm all around it.
Allow me to explain a few things, mainly why… the switch to Tpad and Carclo.
These lights were originally Flawed by design. Optics were crushing emitters and ruining them. My reasoning to swap all parts inside was to keep the looks of the light and make it GOOD. Make what I had work again and make it better. Carclo optic has 4 legs to properly support it under pressure. But the Carclo optic does Not fit the original quad board. Tpad quad was made for the Carclo…
Now the copper head has two shelves to support the optic from crushing the emitters. This is where I am unsure if the Carclo will work inside the head now even if the size it reduced to 22mm to fit in the head recess. Honestly the original optic has a cleaner spot than a Carclo and the original optic already fits in the head. If I were to MOD a Newer S41S with redesigned head, I would simply swap the emitters to the original board and keep original optic. Original board is Nichia 219B or C size which is also XP size… XP-G, G2, G3, L and L HI.
But you may still want to consider the MtnE Fet drivers with Bistro to get a programmable thermal sensor to kick back modes at your desired temperature. Not just a blind timer control.
If you decide to reflow emitters onto an original board, be aware the original board is also flawed.
You MAY have a board where the Red wire is soldered to the Minus and Black wire soldered to the Plus symbol. Emitters are flowed in reversed polarity to “FIX” the flawed board design. Pay attention to all this and make sure you install the emitters and wires accordingly. Same as they were.
If your original board is wired as red to + and black to - do some research to make sure you want it that way. Reason is that the MCPCB retaining screws are sitting on top of the POS traces and are only insulated by the tiny plastic washers. This could possibly cause a direct short and a Bad Lithium Ion Battery day… inside a closed container. 
I’m leaning towards the TPAD + carclo to fix all the little design flaws.
Did you have any issues with the height of the new set up? It seems like the stock set up sits taller and the TPAD + carclo will rattle loose in the head?
Tpad and carclo fits fine height wise. I had measured each but can’t remember each set, it fits fine.
Tpad does have better traces for higher current.
But as I mentioned, if you buy the current versions it will have the shelf in the copper head, it is machined into the copper. If it interferes it can be ground out.
It’s okay for the S41*S* because with the 40 seconds limit it doesn’t get too hot.
The aluminum S41 could probably handle it a bit longer.
the ASTROS41S promo code does not work anymore. Any other alternative?
https://www.aliexpress.com/item/Astrolux-S41S-Stainless-Steel-Mini-4-7modes-1600LM-4x-Nichia-219B-XP-G3-G2-A6-LED/32782993188.html?spm= 2114.01010208.3.99.QJBlJc & ws_ab_test = searchweb0_0, searchweb201602_3_10065_10068_10000009_10084_10083_10080_10082_10081_10060_10061_10062_10056_10055_10037_10054_10059_10032_10099_10078_10079_10077_427_426_10103_10073_10102_10096_10052_10050_10107_10106_10051, searchweb201603_9, afswitch_5 & btsid = 7c71fece-f067-449e-8984-152fd2a3794a
Strong first post.
The store also has a coupon for $2 off dropping the price down to $25.70!
I could not resist, I had to grab one for that price.
Wow!
Is this still the old version with problems or does it have the updated head?
Guess I will be finding out, as long as it is not glued I am happy. If it is then I will sell it.
Hmm? Not helping. 
LOL, I have no idea. You could try sending the seller a message, although I would not hold my breath that they even know what you are talking about and/or could answer it if they wanted to.
I know it will be a working light or aliexpress will refund me so I figure for that price it is worth the risk. But thats just me.
Yeah, how do we know that BangGood didn’t dump the rest of their stock of dodgy lights upon this poor unsuspecting soul, who is now reselling them on AliExpress? Or it could be BangGood themselves selling via an undercover name.