That's nice with the 18350 tube! Is that tube for the Pro specifically? If not, where from?
Found pics of the extra soldered on brass ring from an Amutorch AX4:
And transferred:
18350 tube is the included tube with the SP40 headlamp. Also sold separately by Sofirn.
The standard 18350 tube from sp40 works, I’m the only one who reported it barely fits so far 
Mine is definitely tight. Tighter than it should be probably. But ultimately it does fit.
Hhmm, think I got a SP40, gotta check!
My SP40 short tube’s threads fit like clockwork. But as mentioned, the springs on both ends are compressed about as “tight” as any light I’ve cranked down. If you were going to keep it an 18350 shorty it’s whole life I think it would work fine though. But the springs might get pretty flat after a while 
Does the SC31 PRO have a FET + 1 driver?
Can somebody test if battery check and charging functions work correctly?
Battery check of my SC31 Pro shows 4.5V and still charging the 35E cell…
Mine indicated 4.2V whereas the battery’s actual resting voltage was 4.05V. It would be nice if Andúril had some feature to calibrate the voltage measurement.
Some beamshots I took yesterday night. The white house is about 120m far away.
Sofirn SC31 Pro (Luminus SST40 6.500K 70CRI) 2.000lm
Wurkkos FC11 (Samsung LH351D 5.000K 90CRI) 1.300lm
Thanks Lux-Perpetua! Probably it is Ok that the battery check indicates higher charge than the actual one. Hopefully the built-in charger does not overcharge the cell.
Can you please try to immediately measure the battery‘s resting voltage with a(nother) voltmeter? If it’s really overcharged way above 4.25V it seems to be a severe problem that deserves further investigation. Thanks for letting us know about it.
The charger is a separate circuit and should be fine.
Btw, I added voltage cal to Anduril, but only to the 2019 version. TK changed the voltage reading quite a bit since, so it would take a little time to port. After years of frustratingly voltage cal'ing each individual mod light for Narsil, finally built it in to Anduril.
I got Anduril working like Narsil: 3C to voltage, 2C next to temp, 2C next to version #. When you are in voltage reaging mode, 4 clicks to calibration.
The problem is that I don’t have a voltmeter 
Need to get one. Therefore I am asking if someone else tested this.
I have a LiitoKala Lii-100 charger, and it is also still charging the cell, indicating that it is not yet fully charged. So most probably it is fine.
Right, anyway an offset of 0.3V is substantial and renders the voltage check feature useless. I wonder what technical issues cause such discrepancies. I suppose this is not a Sofirn-specific problem but more likely a correlation between a certain driver component and Andúril.
Maybe this could be a worthwhile feature to incorporate into Andúril 2.0? I talked to Sofirn about the importance of an accurate thermal calibration today. As it’s probably a PITA for any manufacturer to do the factory calibration for each single flashlight, it will need to be highlighted much more in a „Getting Started“ section of the manual. Adding a voltage calibration would fit into this section seemlessly.
Did some research on this. Best as I can tell without pulling the driver, it's a FET+1, based on:
- no 7135's on the underside of the driver
- if there was a bank of 7135's, they would have to put them on the vertical board where the USB charging is - doubt there's enough space
- I can clearly see a slight flicker at about 0.35 amps, coinciding with the 7135. Ramping up to the default ramp top of 3.85 amps, I can't see any other flicker in that range, and if 3.85 amps was the top of the bank, there would have to be 11 7135's in the bank - very much doubt enough space.
Btw, the bezel is glued with blue stuff, probably Loctite. I got it open with sticky blue gloves, but was a little tough, not too bad.
Using a very good VTC5D cell, with the SST-40 6500K: 7.9 amps at the tail, 2240 lumens at start, 2070 lumens at 15 secs, 19 kcd (276 meters). The springs don't look like anything special - bypasses would probably get a bump.
I'll probably at least attempt to remove and get a good look at the driver.
Noticed some odd readings from mine as well. 4.3 when its 4.14 (right after charging)
One time it blinked out 3.3 first then 3.8(actual), even the temp check will go up a couple c after first check.
Checked charging voltage on mine.
Charge terminated at 4.2 blinks indicated by the light.
Digital multimeter showed 4.14 volts.