For that price i would want a sub 
who wants a cookie
RDR, thanks for offering to test. But I hope you do it not just for me, it is for all BLF members who are considering BTU and also to prove your assumption BTU can be used for long time in Turbo mode. I think your camera should have video recording function. This is huge effort as we seldom see people do long time runtime test except some professional flashlight reviewer, if you record it down, you can refer back to it later. We can think about how to publish the file later. I uploaded 3 hours video files to Facebook before, it can be done especially at night when lines are smooth.
I can take your word for it since you can’t upload big video files, maybe 2 minutes interval is better as that will give us 10 readings for 20 minutes.
To other who mention about underwater performance, I don’t recall BTU has the specification about it. I mean even someone tested his BTU can submerge under water, that doesn’t mean your BTU can. It is not stated to have IPX rating. So buyer still have to take their own risk with no manufacturer warranty if they want to submerge it under water. Of course, quite rare people want to submerge their flashlights under water except some reviewers got their samples from manufacturer.
umm the rear rubber seals on the btu are not thick enough for proper sealing .i noticed
oh and fronty can you test the output with and then without the lens .if theres a major diffrence il bug Ric to send me a AR coated one
I should be able to do that. I want to measure the lens size better anyway for possible upgrades later, so I can put it on the lightbox easy enough while I do it.
I have the ability to record that long, no biggie there. It’s the uploading that sux. But let me see what I can do. Ill charge the batteries up and attempt this in one fashion or another tomorrow if I can. I’m curious myself at exactly what time it kicks off turbo, exactly 3 minutes or does it depend on conditions, etc. Too bad I don’t have a temperature gun to see hot hot it gets.
Anyway, again ill see what I can do.
I have an IR temperature probe. I’ll be doing a 20 minute turbo test on this light when I get it. I can live with 3 minute turbo, but I’d really like to be able to reprogram the driver so it had a 10 or 20 minute turbo.
I just went out and bought a Ryobi Tek4 Lion Infrared Thermometer - a temp gun. So I’m good to go in that aspect. If I am going to test any light on run time, multiple turbo bursts, etc., regardless of BTU, TK75, quark or whatever, I want to play it safe and know how hot the lights are getting. If any get too hot, I will now know and can shut them down before damage occurs.
I’m not sure though exactly how hot is too hot. From memory, I was think temps up to 140F (60C) are fairly normal and ok in hard driven lights, but at what point is a light get too hot? I welcome any input on this guys.
wellfrom i understand from my laymans view when led soldered on to the star in the first place,the temparature exceeds above 200 celcius and dosnt harm the led so i guess the driver is the one to watch out for thatl fry before the led does .The more cheaply its made the faster it may fail due to heat.
some observations
-il remove the led centering plastic piece and put in another "flater one. i feel that the "raise" edges are preventing the emittter from striking the sides of the reflector fully .the whole white plastic is like a wall around the emmiter itself!
edit-oh well i tried it :) the beam profile sharpens up a bit. no major changes . So the plastic centering things may be just fine .my bad but im still gona pimp this light up some more
does this look like a u2? .how can one tell?
you really cant tell…
The last time I saw this view of my BTU…. Things went incredibly wrong…. LOL
hahaha . Dale you and i both have the same crazy curious mind .
I have ordered 3 new xml U3 with 20mm star and will change it just for fun :)
will use a more expensive thearmal paste . Silver artic that i use for computer cpu .
thermal paste has to be a very very thin layer just to form a solid bond the 2 metals to transfer heat . thermal paste just "fills up " minute uneven surface . theres no need to dump it like toothpaste !!
I will will also make a large plastic or metal ring 3mm that goes over all the 3 stars and screws neatly . therel be 20mm hole even cut in the large plate thatl keep all stars centered :)
DO NOT let the aluminum heat shield spin on reassembly… That shit wont go good for ya…. Well it didnt me.
Yes . thats the good thing about the btu . All screwed up parts can be changed easily . Rumsfeld would call it the mother of all hosts. iv changed the driver to DRY and then back to the digital driver now :)
this is what im looking for . to make to buy
http://www.fasttech.com/products/1611/10001285/1106805-3x1w-50mm-led-heat-sink-aluminum-base-plate
Guys we finally got a good test done on the BTU and the TK75. Even did a video clip of the whole thing. Did about a 22 min runtime test on turbo. Did the test simultaneously for the pair, alternating each on the lightbox. Also put my just purchased today infrared temp gun to good use, by testing the lights every minute or two for head and handle temperatures.
And I did a lumen test on the BTU with and without the lens.
We’re just trying to get the huge file uploaded and get all the data gathered up. I will then post all the results on my BTU vs TK75 thread I did a couple weeks ago.
I don’t want to mix my data with the’s data. This is his thread after all.
So later tonite or tomorrow after work Ill get everything posted up.
you da man fronty thanks
i just purchased this u3 from fasttech and will change it on it my btu
https://www.fasttech.com/products/1189702
reason for the 20mm star was so that the soldered parts will further apart givingt lots of room for the reflector seat to settle on top of it flat
Just posted up all the data and the video on my BTU vs TK75 thread. New info on post #125
Ahhhh I’m tempted to get it for $120!! The extra $30 can be used for some good batteries. What batteries are you all using?