LG 365nm UV led tested (LEUVA33W70RL00, from Simon)

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djozz
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LG 365nm UV led tested (LEUVA33W70RL00, from Simon)

This is the newest 365nm led that the Convoy aliexpress store has for sale, although it has been on the market for at least 2 years, just not affordable for private buyers until now. Simon only sells it already reflowed on a 16mm copper DTP board and that is how I tested it. Unfortunately they (I ordered 2) were extremely dirty, so I had to do extensive cleaning of the die (tissue and isopropanol) before I could start the test. Here’s the two boards that I bought, the left led I already cleaned for the test. (It is not competely clean, I wished Convoy sold the bare led in original packaging)

Compared to the previous LG 365nm led that was for sale on the Convoy store, which was already among the top performers of the 365nm leds that I measured sofar, this has a bigger die and promises more output. Let’s see. Here’s the new LG led compared to the previous one, for the picture they were wired in series so they receive the same
( <50mA) current:

I used my 2017 method for measuring output, deriving the output indirect by measuring UV-light induced fluorescence in uranium glass. I defined a unit called djozz-mW that allows me to compare different leds and has hopefully some relation to the actual radiant power. This being a rougher and more indirect method, do not expect the accuracy of my white led tests. For details, see link.

The output is a bit better than the former LG led but seeing how much larger the die is I expected a larger difference. But what is more relevant is that this led has almost 0.3V lower voltage at the interesting currents. That makes this led clearly more efficient than the previous generation, and easier to use in current-regulated flashlights.

The surface brightness of the die in his new led is actually a bit less than the previous generation: the limited higher output does not make up for the much larger die.

Edited by: djozz on 01/05/2019 - 20:06
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Thanks for the testing djozz. The lower vf should help alot with single cell builds. Beer

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Hey Djozz Nice work.

Today I just finished 3 Sofirn C8f triples with these new LG led’s based on your previous testing and posts. I already had a c8f with triple Seoul Viosys Z5 to compare it with. Anecdotally both lights put out similar quantity of light but the hotspot on the LG light is about twice the size. (the Z5 seems to throw twice as far). Also I had the same problem as you with dirt and wish they just sold emitters. Thanks again for putting in all the work to do this testing.

In another post you mentioned a relatively high power 75mw UVC emitter. Do you know where I can purchase on one of these ?

djozz
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You have been busy! Smile

Yes, in my test above, at 1.6 A, the new LG puts out just 6% more light than the old LG that performed the same as the Seoul Viosys led, assuming all currents are the same. A 6% output increase will hardly be noticed especially when the hotspot has a different size.

A 75mW UVC emitter costs hundreds of dollars, as far as I know (example). Coincidently Scientist may be sending me a high power UVC led for testing but I would not spend that money on one myself.

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305nm 100mW is a bit more affordable but as UVB less efficient to kill bacteria
https://shop.irtronix.com/products/lg-305nm-100mw-leuva66h00ku00

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Yeah Djozz I may have a problem shipping those out of the country. I will PM you if I can get approval.

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Scientist wrote:
Yeah Djozz I may have a problem shipping those out of the country. I will PM you if I can get approval.

Sure, no hurry, I see it as a lucky opportunity if you succeed Smile
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djozz wrote:
You have been busy! Smile

Yes, in my test above, at 1.6 A, the new LG puts out just 6% more light than the old LG that performed the same as the Seoul Viosys led, assuming all currents are the same. A 6% output increase will hardly be noticed especially when the hotspot has a different size.

A 75mW UVC emitter costs hundreds of dollars, as far as I know (example). Coincidently Scientist may be sending me a high power UVC led for testing but I would not spend that money on one myself.

If you do no torture test on this LED I may buy it after you are finished

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LOL, such an expensive led is not going to be torture-tested for sure Shocked , but I will not sell what I have not payed for, sounds not very fair to Scientist.

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Thanks for the testing djozz.

Is the new led on the left hand side still dirty in the last picture?

 

djozz quotes, "it came with chinese lettering that is chinese to me".

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MRsDNF wrote:
Thanks for the testing djozz.

Is the new led on the left hand side still dirty in the last picture?


No, it is the cleaned one Sad , probably it will not influence performance but the silicon has some pits here and there.
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Probably not the correct place to ask this question, but was wondering…

Convoy sells the Convoy S2 with LG UV LED. I wonder if that Convoy S2 uses the older LG or the newer LG UV365 LED?

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Thanks again Djozz for the testing!! Djozz-mW...that's funny Big Smile 

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djozz wrote:
LOL, such an expensive led is not going to be torture-tested for sure Shocked , but I will not sell what I have not payed for, sounds not very fair to Scientist.

I can Pay Scientist

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Thanks for the test, djozz.

djozz wrote:
But what is more relevant is that this led has almost 0.3V lower voltage at the interesting currents. That makes this led clearly more efficient than the previous generation, and easier to use in current-regulated flashlights.
Looking at if from the other direction it means the radiant output at 3.7 V is not 1070 djozz-mW (at 0.8 A) but 2100 djozz-mW (at 2 A).
That is a huge difference.
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This is probably hijacking your thread a little, but the knowledgeable folks who I have conversed with over the centuries are here, and the topic is UV LEDs.
Despite all the recent claims of 4 watt, 5 watt, overdriven, turbo Convoys (7135 drivers), I believe there ain’t no such animal. The engineers in our fluorescent mineral group have watched the ridiculous power claims climb over the past three years with amazement At the power levels folks are claiming today these little lights should literally be burning your hands. They aren’t – this blog post explains why, all comments welcome: Convoy false power claims

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pirateo40 wrote:
This is probably hijacking your thread a little, but the knowledgeable folks who I have conversed with over the centuries are here, and the topic is UV LEDs. Despite all the recent claims of 4 watt, 5 watt, overdriven, turbo Convoys (7135 drivers), I believe there ain’t no such animal. The engineers in our fluorescent mineral group have watched the ridiculous power claims climb over the past three years with amazement At the power levels folks are claiming today these little lights should literally be burning your hands. They aren’t – this blog post explains why, all comments welcome: “Convoy false power claims”:https://www.naturesrainbows.com/single-post/2015/05/01/Convoy-S2-365nm-F...?

dude the 7135 is a linear regulator

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Sure is, but I don’t understand your point

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pirateo40 wrote:
!https://static.wixstatic.com/media/f4ef11_7117d680101145c9b6a53dddfd6ffd...! This is probably hijacking your thread a little, but the knowledgeable folks who I have conversed with over the centuries are here, and the topic is UV LEDs. Despite all the recent claims of 4 watt, 5 watt, overdriven, turbo Convoys (7135 drivers), I believe there ain't no such animal. The engineers in our fluorescent mineral group have watched the ridiculous power claims climb over the past three years with amazement At the power levels folks are claiming today these little lights should literally be burning your hands. They aren't - this blog post explains why, all comments welcome: "Convoy false power claims":https://www.naturesrainbows.com/single-post/2015/05/01/Convoy-S2-365nm-F...

 

I'm not sure what you're getting at. You may be correct regarding the high Vf of the UV LEDs preventing high output on the UV Convoy, but the Convoy hosts are capable of dissipating over 7W of heat. I've personally run a Convoy on a fresh cell for hours at approximately 2A. Not much sag on that cell, but I'll be generous and assumed 2A * 3.5V for the power dissipation. For short periods, they handle significantly higher power well - not just the stock 2.8A that the white Convoy's come equipped for, but so-called hot-rodded Convoys can pull currents in the high teens.

 

Even your own chart shows the Convoy doing 3 Watts at 3.9V, which could be sustained for a while before the battery got that low - definitely more than just a few minutes.

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700mA is very little current, it won’t burn your hands (but it could damage the Nichia LED if the heat transfer to the star and pill is not good enough as that LED is quite small, the LG LED can handle more current but has more visible light). Even 1400mA shouldn’t get too hot. 2100mA (6×7135) and 2800mA (8×7135) can indeed get quite hot to painful levels if left unattended. There was a temperature test of the 8×7135 driver: http://budgetlightforum.com/node/52757

I guess that a 4.35V cell like the LG ICR18650E1 would be better for extended usage of the Nichia version.

Edit: you are making your claims based on a ‘typical’ 2200mAh cell. Nowadays 2200mAh would be either an obsolete or cheap cell, or a cell optimized for very high current for power tools or vaping (20A-30A) rather than capacity, not a typical 18650 cell. A modern cell 4.2V cell like the NCR18650GA can keep the voltage much better. In fact a 4.35v cell isn’t a large improvement over the 18650GA. From HKJ’s battery comparator :

e1000
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It means a 7135 based driver will maintain a constant current until it can’t sustain it anymore. So a 1×7135 (standard bin 350mA) driver will maintain 350mA , nothing more, nothing less until 3.6V ish, and shortly after that turn off. It will not dim from 4.2 down to 3.6 unless you apply PWM.

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Not too worried about heat, just driving voltage. But that said, UV LEDs are much more sensitive to heat – just look at any graph, derating starts at 40c on most of them. Of course hobbyists can do all kinds of neat things, drive them harder, etc. But production flashlights to the masses, probably a bad practice.
As far as voltage goes, drop below 4 volts and the current to the average UV LED drops drastically. 3.7v (rating for lithiums) and it really sucks.

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e1000 wrote:
It means a 7135 based driver will maintain a constant current until it can’t sustain it anymore. So a 1×7135 (standard bin 350mA) driver will maintain 350mA , nothing more, nothing less until 3.6V ish, and shortly after that turn off. It will not dim from 4.2 down to 3.6 unless you apply PWM.

Don’t think so. The driver just goes into direct drive mode. The LED will light (in the case of an LG or Nichia LED) as long as the battery voltage is high enough >3.0V~, but will progressively become very dim as the voltage drops from 3.9v to 3.0v (or so). PWM another story, I’m talking about single mode drivers, no smarts. edit – keep in mind that UV LEDs expect ~4.0v

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e1000
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pirateo40 wrote:
e1000 wrote:
It means a 7135 based driver will maintain a constant current until it can’t sustain it anymore. So a 1×7135 (standard bin 350mA) driver will maintain 350mA , nothing more, nothing less until 3.6V ish, and shortly after that turn off. It will not dim from 4.2 down to 3.6 unless you apply PWM.
Don’t think so. The driver just goes into direct drive mode. The LED will light (in the case of an LG or Nichia LED) as long as the battery voltage is high enough >3.0V~, but will progressively become very dim as the voltage drops from 3.9v to 3.0v (or so). PWM another story, I’m talking about single mode drivers, no smarts. edit – keep in mind that UV LEDs expect ~4.0v

and I’ll repeat, 7135’s are not direct drive

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ggf31416 wrote:
I guess that a 4.35V cell like the LG ICR18650E1 would be better for extended usage of the Nichia version.

Maybe a little better but according to the graphs it still drops below 4.0v pretty quick it seems. But in our market we have a bunch of people who have no clue about batteries and buy them off Ebay, your local vape shop, Amazon, etc. No idea what they’re gonna get (except the cheapest). In fact, folks selling Convoys to the mineral market on Ebay and at shows are including really junk batteries.
I’ll dig into the one you linked to see if we can get a little better run time – thx for the link. But sadly, won’t help the general population.

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e1000 wrote:
and I’ll repeat, 7135’s are not direct drive

…and I’ll link this: http://budgetlightforum.com/node/51300
“AMC 8*7135 3A CC driver is in fact direct drive” (but I’m always eager to learn)

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Linear driver are never in direct drive.

As long as the battery voltage is high enough, constant current will be sustained.

The problem is that many lights don’t have an optimized current path. It’s not much of a problem with current low VF LEDs…

But it is a problem with high VF LEDs.

Voltage drop over the springs, over the switch, and the wires can be solved.

Using copper alloy springs, thicker 20AWG wires and a thick mechanical/FET switch, we can get max regulated runtime on UV LEDs.

The perfect driver for UV LEDs would be a linear/boost driver.

My very own high current Beryllium Copper springs: http://budgetlightforum.com/node/64047
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

e1000
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pirateo40 wrote:
e1000 wrote:
and I’ll repeat, 7135’s are not direct drive

…and I’ll link this: http://budgetlightforum.com/node/51300
“AMC 8*7135 3A CC driver is in fact direct drive” (but I’m always eager to learn)

Right so since UV emitters require 3.8V it’ll sag once it hits that point, but it’s NOT what you make it out to be, certainly not what’s in your article. With a 2*7135, you never get 4.2v, it’s 700ma @ 3.8V. To compensate, you can just use more 7135’s.

pirateo40
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BlueSwordM wrote:
The perfect driver for UV LEDs would be a linear/boost driver.

I guess that’s my point exactly. UV LEDs require a boost driver to run off 3.7v and lower, a buck/linear at 4.2v. But problem solved if you go to a two battery solution and driver, but not feasible for a Convoy as marketed. (Please let’s not get into CR123s – whole ‘nother set of problems).

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pirateo40
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UV emitters range from 3.7v to 4.2v. Out of the hundreds of LG parts I’ve used, the ones I have tested are all 4.0v. The Nichias I have tested are also 4v. I wish I could get the lower voltage bins, but not easy, and probably pricey? 7135s will drive the LED at its Vf as long as you supply a tad more at the input.

Mark

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