If you go with the TK75, you won’t regret it. Again I love my BTU and wouldn’t consider trading my brother lights, but its mostly a personal taste thing. I actually prefer the beefier feel of the BTU. But likely most people would prefer the lighter weight of the TK75. And if you intend to use one of these for long carry at work - the TK75 is the obvious winner there.
The TK75 weighs less than the BTU by a fair bit and is even lighter than my TN31. To me it feels good in your hand. It is a very well thought out design.
That would be an interesting experiment. If it goes along with other XML’s, you might end up with a 2000otf 900m thrower. Would be impressive if it worked that way. But I’m not brave enough to try it and I don’t wont to lose 1/3 of its output, even though it has some to spare.
I trashed 3 XML’s attempting a de-dome,so I gave up.Thanks for all the good info about these two lights,I think I know which one I want now.
Very informative and even-handed comparo. Thanks.
The thermal pathway is often more important than sheer mass.
Fenix continuous Turbo runtime is 75 minutes with their 2600mAH 18650s, that means each battery is drawing 2.08A in Turbo mode. Total is 8.32A with 4 batteries, drive 3-LED, that means each LED is getting 2.77A if no loss. All these show that TK75 is very well designed in efficiency and safety for both batteries and LEDs. I don’t blame BTU can’t meet Fenix efficiency. But lumens wise it should win all the way, now BTU only advantage is throw of 100m more that is not practical at all. And I can tell you my practical gain from SR95S UT compare to TK70 is only the 100m-200m range. Below 100m, SR95S UT is brighter but TK70 flood better. Beyond 200m human can’t see very clear anymore unless it is very big object at distance.
rdrfronty, do you have lux number for 5m or 10m? Would like to see how the lux number compare to 50m lux number.
At 50m, it will be 2500 multiplying lux reading. Your lux reading for BTU will be 124k/2.5k=49.6 lux, and TK75 will be 94k/2.5k=37.6 lux. These readings are close to noise floor if your meter is not good enough.
I totally respect that the BTU throws further and seems brighter, however the seller for me with the TK75 is it runs on turbo much longer, and you can get battery extensions for incredible run time. In a perfect world I’d have both, but if I’m going for a 5 mile walk thru the bush at night I’m taking the Fenix.
I don’t have 5m and 10m reading from last night. But we tested both lights twice at the 50m, both times being with in 1 lux. I will test them again later when we do beam shots in a week or two. I’m just waiting for my TN31mb to arrive first.
But I know those numbers are very close to true considering the fact we actually walked at the true distances last night and measured the true throw for both lights. And that distance was measured using a 100m tape measure. The 124k for the BTU is equal to 704m and we were able to measure in the .2’s in lux at a measured 700m, and then only in the .1’s in lux at 800m. The same worked out for the TK75. It’s 94K calculated out to 613m, and we measured the TK to have in the .2’s at 600m and then only .1’s at 700m. Now my meter, like most only reads in the tenths of a lux, so I can’t narrow the max throw to an exact number, but it’s obvious that the BTU can do right in the 700m range and the 600m range. How easily and how steady the meter holds these numbers helps to tell me if its likely low in that range or higher in that range.
The throw numbers are correct + or - a few lux or percent. We tested them to many times and in two many ways to be off very far.
Makes good sense. If I was going for a long trek, I too would take the TK over the BTU. It does have the longer run time with 4 cells and the lighter weight. Truthfully I would take a smaller light than either of these though if I was going on a longer journey. Now the longer turbo to me is a moot point though when you consider the highs in the equation. The high of 2160otf for the BTU after the turbo kicks off is almost double the TK and higher than 95 percent of the lights on the market can do period.
I think it all comes down to personal preference when you get to lights of this caliber.
God the BTU is such a big, ugly, heavy light…
Well the BTU has three U2 emitters that are driven an estimated 3.8a each per Ric and cnqualitygoods. Now considering the 2880otf I get in total, that equates to 960otf at 30sec per emitter. That is actually pretty spot on for a 3.8a U2 emitter with decent heat sinking. We’ve got U2’s that do worse and some that do better. The U2’s with slighter better output is the TK75 its 975 per led and the best - TN31 with a measured 1120otf at 30sec. Though I’m pretty sure it’s driven we’ll over the 3.8a. So personally I’m totally cool with the 960 per emitter and 2880otf total the BTU gets.
Besides considering the level of these two lights, the measured 45otf difference between the two is equal to about 1.6% difference. That’s closer than most lights of the exact same type would be. And a good chance the next TK and BTU tested might flip flop with victor and winner with bin variances and etc.
I agree totally. Both would be awesome lights for anybody to own.
Well that’s not very nice. I like my big, ugly, but beautiful to me BTU
But sure, no doubt the TK75 is a more attractive light. Can’t argue with that. I do truthfully prefer the heavy weight of the BTU though. Of course keep in mind I have the even heavier SR90. So powerful lights with “heft” just feels right to me.
It’s a MANLY light to be sure! Anyone with a limp wrist can purchase the 75 as to not injure their delicate nature…. Bwah ha ha!!!
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Hey Dale, have you got a good chance to get your beasty out yet? I’m really curious to see how your upgrade did on your BTU. Should be a really big jump over your old NW setup.
The pics suck though… ( 2 much beer )
