Ok, just theoretically speaking…
I’m still not sure I need one. It would be handy for some things… and useless in general.
I was looking at some miscellaneous stuff on AliExpress and I saw the Convoy S2 UV flashlight.
Some people say to get the S2 because it has a filter while others say to get the S2+ and the filter additionally just because it’s a Nichia. There’s also the C8, S12 etc. and that’s just from Convoy.
I have no real use for a UV flashlight other than maybe checking for leaks, UV pen, checking documents/paper and maybe curring glue.
Would the S2 for $25 be enough for that. I have no feeling how strong the throw is on it. If I need to get 6 inches from the diff to see a leak it’s not very useful. Same goes for searching rocks and looking for other reactive stuff in the woods.
Is something like that enough to cure faster UV reactive glue or solder mask?
It would be just fine for all of that. For leak detection it’s great for most applications and you may even want to use it without the filter for that, depending on the particular dye. Throw with UV isn’t quite as straightforward as with visible light for a number of reasons but in general I’d say the S2+ with the Nichia and a filter can reach out a good 15m give or take. The Nichia at one time was definitely preferred but then the LG emitters came out and those could handle more current and heat a little bit better. I think LG is out of the game now and Simon has started using the Seoul Vis emitters and they’re on par with LG as near as I can tell (I only have one but looking closely at all the data sheets they seem about the same). I think Simon still wisely limits the current on the Nichia model to something just over data sheet maximum.
Since I’m in the US and we have that dumb patent situation about selling lights with the filters, there are lots of models that I can’t see when I visit websites like aliexpress or banggood (or sometimes I can see them if I google it and land on a product page that way even though they won’t ship to the US). If you’re after more than the single emitter small reflector of the S2+ then you might consider one of the single or triple C8 host models out there. Those will give a little more oomph to both range and area illuminated (might be handy for glue projects depending on size, and leak detection for the same reason). If a C8 model doesn’t come with the filter then you can buy one for a few bucks (not too long ago those were really hard to find but they’re all over now).
These eat batteries somewhat quickly and derate just as quickly, so a fresh cell and anticipating the relatively quick drop in output will help to plan for your uses. Just the nature of current UV emitters. For short use times they’re fine and if you can use them effectively at low settings that’s even better, but if you might want longer runtime or more consistent output then one of the more expensive models that runs 2S cells with a buck/boost driver is the way to go.
To give you an idea of looking for things in the woods….S2+ with Nichia does fine but running on a fresh Samsung 35E 3500mAh cell it will start out nicely with bright throw, but after 15 minutes or so on high with his stock driver, the output drops significantly and becomes more like 3-5 meters of useful throw, dropping steadily. This is mostly due to battery voltage since the UV emitters need more than our white emitters typically do, even at these lower currents. Really fun to use, though, and there’s a lot to discover, some things that you might not expect to fluoresce (and many more things that you might expect but do not…). For longer walks, maybe carry a spare cell to swap out.
A while back I built an S2+ with the LG 5W 365nm emitter (basically equivalent to the Seoul Viosys 5W emitter) and Simon’s 2S 1500mW single mode buck driver. I use two protected 16340 cells. It’s able to maintain peak output until LVP kicks in. I prefer this to the quickly diminishing output of the 1 cell 7135 driver versions. Forward voltage of these emitters is just too high for single cell use without a buck/boost driver.
I also built a C8 with the same emitter and driver. For this one, I use 2S 18650 with an extension tube.
I don’t recall what they’re calling them but the couple of big rockhound web sites that sell flashlights have them. They are grossly overpriced. Basically a Convoy-or-similar C8 host with a tube extension and then of course the magic is in the driver (they may have to include a licensing fee or royalty in their retail price, not sure, but the prices are just a little ridiculous, imho). If you need links I can get those later tonight, can’t even remember the main web site names at the moment, sorry, but should come up easily in a search.
Regardless of your intended us, and regardless of how powerful it really is, in the interest of erring on the side of caution I would encourage the use of a good pair of safety glasses. Most UV rated safety glasses block 365nm but if you want to block 385nm/595nm as well you may need to read further into the literature. For example not all Bolle block 385nm but most Uvex do.
It’s not so much about throw but intensity. If you are searching for fluorescent minerals outdoors during daylight, it’s much easier to see the fluorescence with a more intense spot.
Thanks, this is exactly the info I looked for but couldn’t find through Google.
Like I said, basically I don’t need it but let’s be honest, we don’t need most of our flashlights. It’s a hobby and it would be fun to explore with it.
I was looking at the Convoy S2 fro $25. I didn’t want to waste money in case it’s usable at a distance of one or two feet so I did some research and found out that many people get the S2. The S2 is $35 and it needs the filter that is included in the S2. It made me wonder if it’s worth the price difference. There isn’t too much info out there and it’s not like you can compare beam patterns like on regular flashlights.
Anyway, the Convoy store is closed for the Chinese New Year so that made my choice easier lol. I have more to research.
Interesting. Did you modify a regular S2+?
Could the regular driver take two 16340s?
What are the benefits of adding the filter? I have the S2+ 365nm and do have a zwb2 filter but assumed it would just attenuate a bit of the UV without many benefits.
I really, really, like what you did there. For now the S2+ suits my needs but if I need to scale up I think I may nick your idea.
What are you planning to do with it? As for me it all depends on the purpose of use, and regardless of how powerful the flashlight really is. As my practice has shown at wall work, as a precaution, I would advise using a good pair of goggles such as Bolle or Uvex, although there are people who work without goggles, but I would not advise this. I am using Convoy S2+ with very good 365nm light.
Basically it just ensures only UV will be emitted from the flashlight.
A ZWB2 filter blocks most light in the visible spectrum and allows only specific UV wavelengths (and a little IR) to pass. It appears black because it’s blocking visible light.
It allows you to see fluorescence without illuminating objects with excess short wave visible light spilling from the emitter.
You must go to very dark places. That was my original reasoning when I got the ZWB2 but then didn’t install it because in my use case there’s always a lot of background light (lamp posts and general scatter) and figured that it wasn’t worth sacrificing some transmittance. I do admit though that it looks cooler.
Have a few light/uv/ir cut pass filters at home I’ve mostly used for experiments with the kids. So expensive though.
