Luminus SFT40 test

Yes, my mistake, got the words mixed up, meant to say the driver but the word wouldn’t come to me so I just called everything board lol. Why is it such a pain to replace drivers but not the LED boards? I would assume it’s likely the removal process? I could imagine stubborn retainers and things like access being an issue, but other than that it should be a case of just soldering the wires off of the LED’s mcpcb, taking out the old driver, putting the new one in place and then resoldering the wires onto the pcb (3 volt, since the Catapult’s literally the only light I own that uses a 12 volt emitter, I do have a Nitecore EC4S that uses a first gen Cree XHP50, but I’m sure it’s the 3v, 5000k version). Or in the case where you’re replacing both the driver and the LED, I assume the LED already comes mounted in some mcpcb varieties u can choose from, so all you’d need to do is gut the light then drop in the new LED/pcb and solder the driver wires to the pcb then seal everything back up?

And yeah, I’d definitely appreciate a video of you doing the mod, or even just a write-up. (although after doing some writeups myself, I think a video is much easier since all you have to do is record the process and upload that, no having to upload pictures to imgur, copying links, writing down many paragraphs, organizing everything, etc) but whatever is more convenient for you!

I’ve never modified a flashlight before, never even cracked one open, in fact, but I AM handy! I’ve always been a tinkerer, I’ve taken car engines apart and repaired em, as well as taken off transmissions and reinstalled them, done other mechanical work and I was also an aircraft structural mechanic for several years in a Lufthansa MRO. All my work was on the Airbus A320 fam. (so A318’s, A319, A320’s, A321’s). They’re all basically the same, just shorter or longer and they have different door layouts (the longer one would have a door in front of the wing and another behind it vs the rest having them pretty close together) anyway that’s enough derailing, I got some new cells in today and just tried them out a few hrs ago and I’m very impressed. Could only try the 21700’s because the 18650’s didn’t work on my lights because they’re too short AND flat-tops. I think if I just solder a nice blob on the tops I should be good, though. Just need to get my soldering iron back from a friend, texted him tonight n he told me he burnt out my old one so we’ll see how quickly he gets me a replacement. Or maybe I’ll just go out and buy one tomorrow and bill him for it for being a hog hehe, I’d asked for it back several times before.

Anyway, the cells in question are Molicel P26A’s for the 18650’s. They’re INR’s rated for 2600mAh and they’re rated by Mooch for 25A. I think Sony VTC6A’s do 20A but have slightly higher capacity. I went with the Molicels cuz I wanted to try something different and they were a little over 4 bucks a pop.

The 21700’s are the Molicel P42A, 4000mAh minimum capacity and tested by Mooch at a whopping 30 amps continuous, and up to 40A at a 75* cutoff. Anyhow, I tested these in both my Lumintop D2 and my Nitecore MH10S and holy crap, after not even a minute on turbo on the Nitecore, the head got HOT as hell. Definitely not gonna wanna use these cells at full whack for extended periods of time, would likely fry most LED’s I think. Wish I had measurement equipment so I could quantify the difference and share my results here, but it’s very noticeable, specially in how hot the light gets so quickly. Maybe I’ll get the gear eventually if I’m so inclined some day. Thanks for all your feedback btw.

Just went back through this thread to read what i missed the first time.

I reflowed the SFT40 in a EA01 (sst40), single emitter, TIR optic. It REALLY increased the visual throw. by a lot. I will have to measure but it is a very worthy upgrade. I still need to bust out the lux meter i bought and have never used....

Only weird thing (i guess)- i bought to Lishen 5000mah 21700 that are rated for 9.6 amps i think, to try and control the amps that way.. well the first time i turned on and went to turbo there was some nasty Angry Blue happening..

I set max ramp to 120/150 and just stopped using turbo (honestly not a big difference between 120 and turbo anyway) and no angry blue and it has been fine.

Now that battery voltage has dropped due to use, no angry blue happening in Turbo anymore..

I need to disassemble and make sure i tightened down the mcpcb screws enough and also need to test the mcpcb for flatness - something i didn't do when i originally reflowed the sft40 on the original ea01 sst40 board..

It made me wonder - is there any good way to control amp output on a light like the EA01 beside the battery you are using? although i do suspect i got angry blue because of a lack of heat sinking going on due to bad mcpcb contact with the shelf or not an acceptable contact due to screw tension..

You can lengthen and reduce the gauge of the LED wires. Adding resistance lowers amps.

Yeah, and purposely using bad (steel) springs.

Ok good to know, thank you. But nothing on the driver itself?

Well, nothing that simple to the driver itself. Theoretically you could find a lower performing FET but that has other risks.

I'm cautious about downgrading springs. In lowering the amps to 8 or 9 for example, that's still a lot of amps for cheap springs and I'd be concerned about melting them, as I've seen/done before.

thanks Tom. Also about lengthening / reducing diamter of springs- just removive the driver and solder on new springs, right? That's the best way?

Don't ask me - I'm saying I would not degrade the springs. If anything, I would add thin bypasses. I don't trust springs unless they are from Hank or are "Blue" springs.

sorry about that- that was a typo- I mean WIRES, not springs.

if I want to lengthen the wires, I would remove driver and desolder existing and solder new onto it? Is that the best way?

Wow melting ? :open_mouth: was it quite thin ?
I mentionned this thinking about the one in the H600 IV, 0.8mm, steel and quite long, about 50mΩ, it gets quite hot (the light draws 6A which a nearly empty cell) . I was thinking shorter and thicker steel spring would do if that exists (because 50 mΩ would be too much).

For lengthening wires, AWG22 is 0.53mΩ/cm, 24 is 0.84mΩ/cm, depending on the resistance needed it could get quite long.

I should add the SFT-40 in my DD calculator ( Graphing Calculator - GeoGebra ) since it has a lower Vf than the SST-40, it helps see the effect of added resistance (but without knowing the current it’s difficult to estimate the light’s resistance)

thank you for this info freeman- I will say that (very unscientific) that once the battery voltage dropped from fully charged to about 4v, the angry blue went away. So of course I don't know what amps it's pushing at that point, but it just be close to being ok, meaning hopefully not a lot of resistance needs to be added to eliminate angry blue on a fully charged 9.6amp rated Lishen cell. Wow.. that was horribly uneducated way to justify my use of "not a lot of" extra wire needed LOL

I'll reduce the wire to as much as 26 or 28 AWG, lengthened if needed. Without the ability to measure amps, it's difficult to test. I'll usually add a tail spring bypass just so that the tail amp readings I get on the clamp meter is what I expect to get with the tail re-assembled, otherwise it's guess work of how much is lost in the tail spring.

Got it that makes sense. Thank you

Another indirect way of measuring current is by measuring the voltage at the mcpcb solder points. This method has many issues to be aware of, but if care is taken to compare values at some normalized temperature, you can get an idea of roughly where your at and then can detect relative changes with mods. Useful if no other method is available.

Looking forward to throw numbers from the EA01. If they sold one with the SFT and 26800 tube and a linear driver to cap the current, it’d be a hit IMO.

Sorry, melting meaning burning off the coating, deforming the steel. I've seen them collapse then breaks the connection because of the contraction. All depends on the quality and it's rare we can get specs on springs.

ea01 modded w sft40 beam shot :)

https://budgetlightforum.com/t/-/66979/25

What battery did you use in your EA01? I also swap my SST-40 EA01 with SFT-40, with new and fresh charge gold Vapcell 21700 the emitter got burn after a few times on turbo mode… black dot in the phosphor :person_facepalming:

Emitter peaked at ≈10.2A in djozz's test. Not all emitters perform the same, and even if the differences are small with just one test we don't know where this one is at.

Setting the limit at 8.8A (in Convoy's ramping driver) is easy, just stick an R050 over the R005 sense resistor. With an R025, or two R050's in parallel over the stock R005, limit raises to 9.6A. Personally, I would stick an additional R050… or not care at all (whereas 10.2A is ≈2630 lemons, 8A is ≈2450, which is 93.156% of maximum output anyway).

Concerning the driver, at this point this regulated linear driver is my favourite, namely due to certain performance hindering shenanigans happened to the other “SST40” linear drivers at Convoy. Hardware wise it is the best one in every respect, although the stock firmware is somewhat limited and may not be everyone's liking.

If someone's going to develop a more common software for the MCU, I would be pleased. Also, porting some firmware from Toykeeper should be easy. :???:

Regards everyone

P.S.: This emitter in CRI95+ would be a blessing.

Wed, 08/11/2021 - 11:23

I used a 9amp 1100mah Epoch 18350. everything was fine

but i was using a Lishen 21700 9.6amp 5000mah, and i got ANGRY BLUE led when fully charged. it was very bad, so i immediately set max stepped ramp to 120/150 and did not go into turbo on a fully charged 21700. once the 21700 voltage had dropped to under 4volts, going into turbo was fine.

But i had the idea of using this less powerful 18350 the other day and i feel like it is much safer. I have not had angry blue since that first day.

I just make a point to make changes Right Away to UI or whatever i can when i see that angry blue happening, becasue that black dot in phospher can happen quick!.

Gents, I need some advice. Seems I ordered the SFT-40 on a 20mm MCPCB. Not sure what that was for, thought I’d get the bare LED. So, is it advisable to use this part in an SST-40 Astrolux FT03? What else must or can be done? I measured about 6A with a 26650 that I ordered with this light. Surely it would be more fun with more amps.

Thoughts?