The gold standard is a high powered mercury vapour bulb, 125 watts upward, but these have been banned in the EU for over 3 years now, so old stocks are getting low here.
By the way, lumens are not a relevant measurement for UV emitters. They are a measure of VISIBLE light. Their definition is based on the response curve of the human eye.
“The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source. Luminous flux differs from power (radiant flux) in that radiant flux includes all electromagnetic waves emitted, while luminous flux is weighted according to a model (a ”luminosity function”) of the human eye’s sensitivity to various wavelengths.”
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“A source radiating a power of one watt of light in the color for which the eye is most efficient (a wavelength of 555 nm, in the green region of the optical spectrum) has luminous flux of 683 lumens. So a lumen represents at least 1/683 watts of visible light power, depending on the spectral distribution.”
I.e.a true (invisible) UV LED emits zero lumens.
Perhaps there is some tenuous read-across, but UV LEDs are also quite different in design and construction from the highly researched and optimised “white” emitters (actually blue, with colour conversion phosphor on top).
The relevant unit of radiant flux is the Watt, meaning Watts out, not Watts in. To talk of lumens, or lumens per Watt in the context of UV LEDs is just ignorant.
For example, Djozz has tried to develop his own method for comparing UV LED performance using standard instruments tuned for the human eye luminosity function, initially using fluorescence of white printer paper, now using the bright green fluorescence of Uranium glass ISTR.
Obviously not. Good to see that you have a grasp of what is possible.
There are many “learned members” here who specialise in dicking around with advertised specs, and pontificating, whilst believing in fairies. Usually never having owned nor touched nor measured such pricey things, never mind tried to use one to attract insects.
You initially asked for someone to make a custom “20,000 lumen” build for you, with a nonsensical specification. I doubt that that is going to happen, even if you can find someone with any knowledge or experience of the (esoteric) subject, never mind mix LEDs starting at 300 nm. That’s very specialist, even high powered 365nm LEDs are still esoteric.
Best you continue your research and figure it out for yourself. Then please tell us about it, it is fascinating.
And no, I very much doubt that any “off the shelf” torch could possibly work for you.
That’s why, in specialist interest groups (entomology etc.), there seems to be a consensus about what actually works, and yes they are always trying to improve these things and are quite up to date with LED technology. But meanwhile they continue to use other stuff that is mature.
Yes, among entomologists there is a consensus, more or less, about what works: UV or mercury vapor bulbs, aimed at a white sheet or with an incorporated trap…and that’s nice, and there are even lamps sold for the purpose but they are wimpy and what I want is a mega superpowered yet portable version of what that have, in LED, because mercury vapor lights are so fragile and get so hot.
I realize my specifications are loony, but it’s because I know bugs, not electronics. I know my goal but have no real knowledge of how to get there- which is why I came here.
So, let me rephrase my question:
If you were me, and you wanted a super bright insect-attracting light that is portable (ie, 25 lb or less and not dependent on a generator or auto battery) and won’t get hot enough to be a hazard, what would you buy?
Well, I don’t know what all the negativity is for. It really isn’t hard to reach 20,000 lumens these days. The highest bin XHP-70.2 can reach over 4000 lumens from a single emitter. So, five of them would have you covered without exceeding the manufacturer’s maximum power rating. Then, of course, you’ll need to add some UV emitters as well. BLF member djozz has tested several different UV emitters, so that data is available to whomever ends up building this thing. Keeping the emitters within manufacturer’s spec should mean that cooling isn’t a problem either.
The biggest issue will be having enough power capacity to sustain the desired output for three hours. You need over 450 watt-hours to do that. I suggested earlier getting lead-acid. You can actually just get one 12V 40Ah Deep Cycle lead-acid battery from an auto parts store for around $100 and be covered. But others have suggested lithium cells and/or power packs, which will be lighter, so easier to carry around. You can get all those 60x 18650 Li-Ion cells you need into a 6 1/2 inch circle. So, the paper towel roll size Enderman mentioned early in the thread would actually contain it all. I just checked at engineeringtoolbox.com. But, 60 of those at around $5 each is going to be very pricey.
Thanks, DavidEF. It’s worth some money to me to have just the right light. I don’t know how convenient it’d be to recharge 60 batteries!! But where there’s a will, there’s a way, right? If I could just plug it into the car or a household wall plug, that’d be great.
Well, with a properly design Battery Management System, plugging in at home to charge it is a real possibility. But I don’t know if there is a decent quality BMS available to the public for 60 cells. Honestly, balance charging is over my head. I know it exists, and I know in theory how it works. That’s as far as I can go. :person_facepalming:
About 20 of the shockli 26650 cells would be enough.
It is not hard to incorporate a charger into a light if you don’t have a strict size limit like a regular flashlight does.
Simply plugging the light into the wall overnight would charge it up, and would be really easy for anyone to use with little to no experience.
This is what is great about making a custom device, you can do anything you can imagine without any of the typical restrictions that regular stuff has.
