Luminus SFT40 test

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.

This 8A “12-groups/biscuit” buck driver at Convoy (marketed for the Osram KW CULPM1.TG or White Flat 4040 2mm²) is also suitable for high powering this SFT40 led (better than for the CULPM1.TG, imho). It's pricey, though.

I'd prefer a universal, high efficiency regulated high power boost-buck driver. A regulated boost-buck driver always ensures the full drive current independently of battery voltage or state of charge (for as long as the input voltage is above the minimum, that is). This way you wouldn't need to care about angry blue overdriven emitters, or always fully charged batteries to get maximum performance. But well…

Does Simon will offer L21A with SFT 40..

This host goes very well with the SFT40. Host L80, Mantaray driver with a stacked R020 resistance and 20AWG cables, 2 20AWG derivations. With the amperimeter clamp I measure 11A and according to my measurements (which can be a bit high) 2620lm and 670,000cd

What’s the reflector inner diameter and bezel outer diameter on that L80?

Nice numbers anyway

Bezel 76mm, Reflector I think 69.5mm x 55mm depth

Mantaray driver with a stacked R020 resistance? What I can remember from having seen it in AliExpress somewhere, the Mantaray driver you are speaking of uses an R015 sense resistance, and claims up to 7A of output. With these figures it is easy to infer that maximum sense voltage is Vsense = Istock × Rsense = 7A × 15mΩ = 105mV.

Technically speaking it is a linear driver or regulated variable load driver. Uses a MOSFET or MOSFETs as variable resistors, and a sense stage to “feel” the flow of current and do its job.

These drivers are set for a particular current. When current goes through them, they sense it in their MCU thanks to its sense resistor and operational amplifier. This allows them to regulate in a sort of conscious way.

The key with these is to adjust the sense resistor value properly, if required. When you change the value of the sense resistor in the driver, you can obtain the new maximum current value by using Ohm's Law. Also, additional sense resistors in parallel add current to the limit. The limit for the stock driver is I = Vsense / Rstock = 105mV / 15mΩ = 7A, this is explained above when calculating the maximum sense voltage. Now, with an R020 in parallel with the stock R015, we have to add: I = Vsense / R020 = 105mV / 20mΩ = 5.25A. All of this being said, Pacolux's Mantaray driver with both an R015 and an R020 in parallel as sense resistors will now allow up to 7A + 5.25A = 12.25A to the emitter before using their MOSFETs to throttle the output and protect the emitter from overcurrent in doing so.

All of this being said, Pacolux is overcooking its SFT40 emitter. I think 7A is plenty for this emitter. If you really need to add something using this driver, I'd use an R100 for 1.05A extra, 8.05A total. This is toast enough. Please consider that not all emitters behave exactly the same, and that one must be sure that the driver fully meets the claimed specifications, because if not final maximum current figures can be different. To illustrate this I was recently setting up a custom S21A with SST-20, using a Convoy 12-groups driver I received months ago as replacement for a recalled defective unit: presuming 60mV sense and R020 plus R050 sense resistors in parallel the unit should have attained 4.2A, but I finally got 4.7A (variations in sense resistor values also matter). Check this here, among other things related to obtaining correct measurements with these driver types when using power supplies.

Does your L80 have a donut hole with a domeless Led? Tried mine with Culpm1, Cslpm1, Cslnm1, also dedomed Xhp50.2. The results for all of them = donut hole :’