I wouldn't necessarily say that the Nichia is better than any of the LG options. UV leds are fickle things, sensitive to heat and derating very quickly compared to our robust white emitters. First of all, the wavelength of an emitter is not precise - all of them will have a little stray white/blue light to them (without a filter) and all of them will vary their peak wavelength a little bit, some more than others, depending on temperature and current fed to them. The hotter it gets (which doesn't take much with these) the more they may stray from their peak or spread out the range adding more "noise" closer to visible wavelengths. The Nichia tends to hold this line a little closer under duress. The LG emitters, including different lines, stray a little more but they stay well within an acceptable range. The LG do tend to handle heat better and while they still derate terribly (all UVs do), they are not as bad in that regard as the Nichia (or at least the Nichia 276A, which is our norm). The LG can also handle a bit higher current and tolerate it for a slightly longer period/duty cycle than the Nichia can. And that brings us to binning, which is the kicker. They are pretty close to one another so if you get a good bin in one and a lesser bin in the other, it can be a washout or a slight advantage/disadvantage. The LGs that I have seen (and own) were binned with lower Vf so basically they're giving a bit more oomph and a longer run time compared to the Nichia...of course this can vary based upon what the driver is delivering and the heat dissipation of the light (both LG and Nichia list the same power dissipation figures for their lines of UV...about 3W if I recall correctly).
The thing is, these are both very good UV emitters and the differences are comparatively small. AND...the filters cover up all the sins. Seriously, the filters are like magic for UV viewing, but whether that matters to you just depends on your desires/use case. Looking for pet stains in the carpet, definitely the filter helps a lot just by helping the fluorescence to pop visually a little better since stray visible light is reduced or eliminated. Checking IDs or currency...filter doesn't matter that much really, although it can ease eye strain if you are doing a lot of that as a bouncer or at a check-in or whatever.
It's hard to find data sheets for LG but if I didn't get the wrong one for the Sofirn mentioned above, it looks like maybe it's using a narrower beam angle on it compared to the LG that Simon used/sold for a bit (now replaced by the Seoul emitter) or the Nichia 276A. If so and it's the 75° then that can appear to give a little more bang for the buck in the reflector and/or use a bit less current to achieve similar output. If it has the normal 120°/130° beam angle then it's not that different really other than the shapes of the reflectors.
So your Wurkkos should be plenty enjoyable and the UV will still be useful to you. I would suggest getting some newer/better cells for it, though, just for the UV emitter's enjoyment if nothing else. If you decide that UV is important to you then yeah, pick up a decent one sometime and get the filter with it. Likely that you'll have to purchase the filter separately and install it yourself, though, because of a jackwad patent that a man has regarding selling the combo together (stupid, really, and a good example of IP abuses, although it was awarded to him). Some sites/sellers ignore it and will ship it to you installed/complete, some just won't ship it to the US at all. But the filters are definitely worth it, and so are the dedicated UV lights if it catches your fancy.
On the SC31 Pro...definitely a nice little light. Go back and check out the charts on Zeroair's review again...particularly the two followup charts AFTER he calibrated the temperature in the firmware. Makes a world of difference and it should always be done first thing. Need an accurate thermometer and lots of clicks, but it's easy to do. What he was seeing in his first charts wasn't poor voltage regulation but rather the firmware reacting to inaccurate temperature calculations. Once he corrected it you can see that the light will hold pretty well over a much longer time period. It's a good light, no worries. And Sofirn's batteries are fine. I mostly have 21700s from them but a couple of their 18650 as well and they're ok. I mostly use 35E and VTC6 in my 18650 lights but the Sofirns have been fine. No worries about explosions, either. These aren't old-school ICR chemistries and they're single cell rather than multiple in series...plus driver controls to aid in overdischarge. Be smart but don't sweat it. Your old batteries should be fine, too, although at this point I suppose they have less capacity and higher resistance, which will degrade performance and increase heat, so maybe keep those for mid- to lower-power lights instead and treat your more powerful ones to some newer cells.
Lots of interesting information.
For now i am sticking to just this light purchase but if i look for more lights in the future i will look at the SC31 Pro again.
Thanks Funtastic, I have been debating on getting a YR1035R for quite a while - I don’t believe I will use it very often.
I am very aware your testing on LR2170SD showing it outperforms 50E. However, current version 50E2 is much better than 50E and performs as good as 50G according to Mooch’s testing. I actually bought some 50E2 from 18650batterystore in April @ $4.49 each so I didn’t see any reason for getting LR2170SD.
Actually Lishen LR2170LA is a quite interesting cell with 4000mAh/35A CDR, but again it priced higher than Molicel P42a so obviously P42a is a much better choice.
What is the advantage of Wurkkos TS21 over sofirn IF25a at same price? TS21 has a smaller head so heat dissipation will be even worse than if25a. Included 21700 is obviously a Lishen LR2170SD but I wonder how long 3500LM could last with 9.6A CDR. ATR kicks in at 45oC - does it have a regulated driver?
Not sure why everyone is so focused on lumens for a small EDC where you don’t usually activate Turbo for very long. I personally grab a larger model if I need that much output and range.
70°C limit and it achieved over 60 sec Turbo - Head 63°C - Body 54°C after 15 min. Something close to that, currently on the loo lol.
TS21
- Compact
- 2 way clip
- Magnetic Tailcap
- Better flood
Nicer looking beam profile
Some find the IF25A to not offer enough flood, looks bad, no thought went into the design it seems. Yes, it’s better at holding Turbo, but I would rather the above for an EDC option
Don’t buy with their battery, I use a Molicel P42A
ANSI
IF25A - 3,040 lumens
TS21 - 2,800
Not much difference considering the TS21 only has 3 LEDs
Bit disappointing that they used a Fet driver when they told us on here it was running a buck.
I would like to add that the older Convoy S2+ uses Nichia 276A emitter with Optical Power Typ. 780mW, whereas the upgraded S2+ uses Nichia 276C with Optical Power Typ. 1050mW, although the size remained the same. It is also slightly more focused (120 degree vs 130 degree). But efficiency improved a lot. Assuming a forward V of 4.4v and forward C of 0.5A and a output of 1.05W, the efficiency is 1.05/(4.4×0.5) = 47.7. So the newer 276C emitter is ~50 efficient, half of the energy it uses for UV light and half for heat. It is quite significant upgrade.
Thanks a lot Funtastic, FET driver and the lie from wurkkos really pissed me off. if25a 4000k is actually floody enough for me. I think SP35 is the same size as TS21 but beam is too focused.
Good point, I wasn't aware of that. Just compared the datasheets and it looks like they made an effort to improve the die for better heat transfer and lower junction temperature (rated at 3.25W power dissipation now), and it looks like the bins demand a little less Vf now as well. Puts it more on par with the LG I think although they still officially list the other heat-related parameters the same as the 276A...makes me wonder if it can actually handle a little more current/overdriving better or not. The derating is only slightly better than before, but really that's an achilles' heel for all of these UV emitters, especially the way we're using them in flashlight hosts.
Realized that they didn’t lie about it, we just misunderstood. Wurkkos said it was FET + Buck which means buck for the charging circuit and FET for the light itself.
