Initially I have the same intention like you - ordered wk30 as my only uv light as I thought I won’t use it often. After playing around for a few days I felt unsatisfied and then ordered S2. I think it is still a good uv light, but saw huge difference after testing both in bathroom. After that I ordered ZWB filter for S2 (you cannot add zwb filter for wk30). The wk30 I received obviously has a different emitter than pictures posted on wk30 review threads here but I later found it is the exact same one used in sofirn sp31uv (no surprise) so believe it is still a 365nm emitter. The S2+ Nichia 365 I bought is the upgraded version with 7135x3 and Zeroair has a test review on it. To be frankly, I think you will eventually buy a S2+ if you are interested in a uv light. I actually like wk30 - it is a good light, 351 emitter has very neutral white light w/o any noticeable green tint. It is also very floody and red light is a big plus.
Yes I believe it is a 365nm emitter, 395nm emitter has lots more visible light and all 2021 wk30s should be 365nm (mine was manufactured in early 2021 according to serial no ). The one I received has the same emitter in sp31uv tested by davestechreviews, but it is different from wk30 review thread posted on BLF.
Yeah these DLG 18650 batteries are dirty cheap so I guess it is the reason why sofirn re-wrapped them. I do see a few has high internal resistance on my vapcell s4+ so obviously QC could be an issue. Other Chinese branded cells like LISHEN have the similar issue. I remember seeing a report saying that the QC failure rate of these Chinese cells is much higher comparing with major brands.
Resistance is never accurate on a charger though, you’d need something like this
I found the Sofirn 21700 5000mAh (Lishen LR2170SD) to be excellent, I reviewed it here I ended up purchasing 100pcs of these from 18650batterystore.
Can’t really expect China cells to match the same QC when they’re priced so much cheaper. They’re decent for what they are, I just wish Sofirn gave the option to bundle Samsung, Panasonic etc.
The older 395nm LED did have visible light “leakage”, but it was bluish/purplish, not too obtrusive.
The newer 365nm LED, which I don’t have in the WK30, but presumably in the SP31UV, which I do have, has an eerie greenish tint to its visible leakage.
The ’31 is a nice UV thrower if you want to spot scorpions, etc., before they’re actually crawling all over you, but it’s in desperate need of a ZWB2 filter. My old/original WK30 is perfectly usable without any filter.
That said, the UV S2+ with ZWB2 filter is the sangraal of UV lights.
Bah, nobody would tell me this before i bought the wrong light…
Ummm, did you ask? 
You’ll be happy with the ’30.
Yes, it was highly recommended
There’s a couple posts on the first page recommending the Convoy S2 UV with the ZWB2 filter
Indeed, i didn’t know until this thread that it was a better UV chip, just that it was another option.
Can that filter be bought as a large piece i can put over the light for the WK30?
While the Nichia LED is better than the LG, the massive difference is the filter
Convoy sell the C8+ with a large filter so perhaps you can ask Simon if you can purchase separately
Better in what way?
Also what does the filter do, i have not actually done any research on it yet, i figured i would play with the light then research filters.
Yep.
The reason you want an uv light is that you want to see things you cannot see. For this purpose S2+ with ZWB2 filter will be the solution. If you search uv 365nm on BLF you will easily find it is the one to get. Don’t take me wrong - wk30 is an excellent flooder with 90 CRI and you also get a decent red light and a regulated driver. What I was trying to say is that wk30’s uv is not comparable to S2+, not close.
I have four types of UV lights (Wurkkos "WK30", Sofirn "SP31UV", Lumintop "IYP UV", and Lumintop "Tool AA 2.0 UV").
All of these lights have 365nm UV LEDs, but only the "Tool AA 2.0 UV" (which supports 14500 Li-ion, Alkaline AA, and NiMH AA batteries) has a factory-included black ZWB2 UV filter lens which greatly reduces the visible light to provide the best UV experience and the difference is easily noticed (especially at night where white painted sheetrock walls appear dark and black when viewed with the "Tool AA 2.0 UV" with the ZWB2 filter compared to the other lights with clear lenses).
AmazonUS lists the Lumintop "Tool AA 2.0 UV" (with ZWB2 filter and 14500 Li-ion battery) for $25.99 and is currently offering an 8% discount coupon for a final price (before tax) of $23.87 but www.myvipon.com occasionally offers AmazonUS discounts on the "Tool AA 2.0 UV" for a final price of ~$16.50 (before tax).
I have multiple Wurkkos "WK30" lights and they are one of my favorite lights, but for UV-only use, the Lumintop "Tool AA 2.0 UV" with the ZWB2 filter is my current favorite. When the "Tool AA 2.0 UV" is "ON" (it has two brightness levels with memory) or when it is "OFF", the lens is always dark and black so it would be difficult to tell when it is "ON" during daylight, except it also has a special O-ring around the dark black lens which glows when it is "ON".
I have had and used the SC31 Pro and the light and the battery are both top quality.
I am a long life, duration kind of guy; you can get great runtimes on that light with the supplied Sofirn wrapped battery.
The same goes for the Sofirn IF25a light and battery combo. Again great runtime and battery performance.
You can trust them.
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.
Why is the WK30 UV chip not as good as the Convoy S2 UV chip?
What differences/deficiencies are present?
The regulation is crap and a new member with one post saying it can be trusted seems suspicious.
You have restored my faith in giving it a fair shake once it arrives 