I’m sure. I didn’t want to see the UCLp upset so I checked, jaw dropped, I checked again and then did the modified L6, same thing. I have all the cells on the charger and will test again at maximum output. 
You know what this means, right? My modified L6 showed 7245 lumens before, with the UCLp on board… that means with the stock glass it’ll be higher, and I can’t wait to see what it shows with nothing in front of it other than the glass shelf in my light box. 
In all fairness, Chris’s UCL glass lenses have higher transmittance than the acrylic lens, if only by that last 1% or so. Seems Simon found an AR coating that rivals the UCL legend.
According to your measurements :
Difference between UCLp and Convoy lens’es is : in stock L6 0.73% and in modified L6 2.92% .
It could be interesting to check with full batteries .
Interesting results. Thanks Dale! Yea, would be interesting to see the beast L6 you got there tweaked for a little more. I've seen more bad AR's then good, I think I've only seen the UCLp's beat them, but probbaly just in more budget lights.
I have one XHP70 P2 1C on a 20mm sitting around here, from back when Richard had them in stock - should have bought 1-2 more. Wonder if/when he's getting more - been meaning to ask him.
I dug out a stock L6 lens from my box where I put them when I get UCLp lenses in as replacements. It’s been my practice to place the blue protective film on the stock lens and write the lights brand and model number and the date on this film, for reference. When I removed the film from my L6 stock glass, (replaced July 1, 2016) it pulled a lot of the AR coating off the glass, ruining it.
So, while the coating might have nice translucence it is more easily damaged.
That said, I pulled fresh charged Efest Red 3000mAh 26650’s off the charger at 4.21V and did a replay on the tests, using the UCLp from my black L6 and the stock glass lens from my Clear L6. The results have me thinking I made a mistake on the first go round, much as I tried to get it right and double/triple checked. Oh well, I can only report what I just saw.
Clear L6, in stock trim.
No lens 4226.25
Stock lens 3815.7
UCLp lens 4081.35
Lest y’all think I’m nuts (can’t blame you, I do) the glass lens has sanded and radiused edges, and of course it’s glass, making it easy to see the difference from the Acrylic lens with laser cut edges that show microscopic ridges. Very easy to tell them apart.
Cells from the modified L6 are still charging.
Edit: The only way I can see that there could be such variation is in the order of testing, cells dropping after getting hit with the 4000 lumen first and ensuing test. I tested this time with the UCLp first, no lens second, and stock glass lens third. First time it was stock glass, UCLp, then no lens.
Dale man why you gotta make me so happy the let the wind out of my sails like that! I know Simon’s lenses are good but UCL and UCLp have a very strong reputation for being the best. Almost sprayed my monitor with coffee with your first couple posts saying Simon’s AR glass was beating the UCLp. That really would be the upset of the year. Still, your last round of numbers show a bigger variance that the other tests…
I think you need to do more tests. 
Ok, on the modified L6. Pretty sure the only real way to get accurate results is to run the light in the test then run it some more to knock the cells down enough for the charger to get a sense of balance on em, charge em up fresh after each run. Because the cells are obviously taking a hit and skewing the numbers.
Fresh charged Basen cells in the modified Black L6 showed, without any lens at all, 7693.5 lumens
I put the UCLp on it and it did 7417.5
Then I put the glass stock lens on and got 6589.5
Gotta be the cells taking the hit on the sheer power.
I’ll charge em back up and take a reading on the stock glass with fresh cells…
Take a reading on the modified light or the stock light?
Too bad you don’t have a bench power supply, it is great for things like this. You can set it to a fixed output and ensure that the cells are not an issue.
Dale, did you check the cells of your luxmeter recently?
I’ve thought about it before, but that’d be just one more thing for me to learn how to use, forget how to use, and leave plugged in til it burned up.
Have a $114 Sparkfun hot air station on the way, no soldering iron as I like my Hakko.
My lux meter is solar powered Mike. hahahaha
Yeah, it’s got a new 9V cell. Comparatively new, anyway. This decade or something. I remember putting it in there but can’t say if it was 1 month ago or 6.
Been taking care of it… the cell that was in my meter was at 8.1V, the new one is at 9.5V. So now I have to start over. Ugh.
On my luxmeter when the batteries start goin low, the lux readings go up. Testing mods, that can be fun - wow that mod was awesome! But when the meter gets to that point, the low batt indicator is always there.
You must have a lot of amps killing the cells - maybe also heat, if you were doing them close back to back.
Stock gets my vote for this test.
So, here’s what I did… I used the modified black L6 with it’s 4500mAh Basen cells and I charged the cells fresh each of the 3 runs. I have a start number and a 30 seconds number for each of the 3 test runs. Before each test, I pulled the cells from my 8 bay Enova charger and measured the voltage. Each time both cells had stopped charging at 4.23V.
With No lens at all, I saw 7,590 lumens at start and 6,900 at 30 seconds.
With Stock AR lens, I saw 7,452 lumens at start and 6,762 at 30 seconds.
With the UCLp, I saw 7,279.5 lumens at start and 6,451.5 at 30 seconds.
So, with the cells at a common start value, fully charged, and with the light cool between runs, it seems pretty clear here. The factory AR coated lens outperforms the UCLp lens. At 172.5 lumens difference, it’s not a huge deal, but still. The factory lens is only dropping 138 lumens as compared to no lens at all. That is pretty remarkable.
Oddly enough, both with no lens and with the stock lens runs the light dropped 690 lumens in 30 seconds. But on the UCLp run it dropped 828 lumens. No obvious reason why.
It should go without saying that an unmodified light will show less difference than the highly modified light of these tests.
Essentially, it isn’t worth the trouble to change out Simon’s excellent quality AR coated glass lens.
4% (@start) to 6.5% (@30 secs) loss for the UCLp that supposed to have a 97% translucent rating. Hhhmmm. It's a fairly big difference - the 4% to 6.5%. I assume the cool down time was pretty long between trials because of the battery re-charging.
What's the thickness of the stock glass lens? The UCLp is 2.25 mm - wonder if that's factor, and if measuring without the lens is somehow measuring differently in the pipe light box, if that's what you are using - or a sphere. I know the pipe light box is position sensitive, but dunno of a lens/distance effect - dunno, maybe not a factor.
Tom, have you ever built one and then taken readings, used it, charged it up, taken readings again? It’s really rare to see the readings stay constant. I once thought it should always do the same thing, every time you tried it, but it just doesn’t work that way.
I think flashlights are female.
Yea, of course - lots of variations and still can't explain them all. Yep, been there... Technically I think there's an explanation somewhere - really think'n sometimes it's the cells since our typical DD FET builds are so dependent on them. Seems like charge cycles effect the cell resistance - whether a full charge or topping off, etc...
I got a lot of confidence in our pipe light box and luxmeters though - seen really good consistency there, when keeping the geometry consistent.
Tom, for the record Dale uses a calibrated light sphere. His comments may not always be P.C. :person_facepalming: but his data is quite solid. :+1: