Luminus SFT40 test

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 :)

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.


6 amps is a bit low, dunno maybe the cell. But the SFT-40 has a lower Vf so if you got 6 amps on a SST-40, you should get about 7 amps on the SFT-40 in a FT03, but of course you can do better than that - spring bypasses would be the first thing I'd do. Think the FT03 uses a bigger MCPCB? If so, you'll have to see if the 20 mm will allow wire clearance, and if you want it secured down, maybe drill and tap screws.

Yes, thanks. I guess if it doesn’t fit, I’ll swap LEDs. Measured the double springs and had very low resistance, but I guess my meter is not good at measuring it. Will bypass it.

Edit: Color is very neutral. Nice.

Sub ohm can’t be measured with a common DMM, you need to pass a known current through the spring and measure the voltage drop.

the ft03 has a 28mm board, it is possible to create clearance with 20mm board if needed but requires sketchy centering ring stacking. 20mm by itself does not clear the reflector bottom. I would 100% reflow the sft40 onto the original sst40 mcpcb from the ft03. Should have no problem with that.

Yes Artie, it’s easy but the LED suffers. For now, the board found its home in a Sofirn SP33V3 that I had no use for. Maybe I’ll reflow it later or buy some new LEDs.