Fenix TK35 (XM-L, 2x18650/4xCR123A) Review: RUNTIMES, BEAMSHOTS, DETAILED COMPARISONS

degarb

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Got mine last night no green. I won lotto.

To respond to man who wrote sunnyway light is as good, "The driver is better in the Fenix lights. " It makes no sense to slam an led with max current where it is less efficient than a direct drive Coleman xpe, then use pulse width modulation to dim it. Even if you only use high, you start out with 4 volt on a led with a forward voltage of 2.8 and are still waisting voltage that should be converted to current. This is one main reason I steer clear of most light in this forum and why I am faithful to fenix.

I have no use for flashlights. Flashlight people must hold their lights, and so must only use them a few minutes here and a few there. But marry them with your work, and headlamp or wrist mounted, is the only way to go. (I tried chest and neck, but light was never where I was looking.)

So, I was a little sick when the light arrived and so darn big and heavy. I can nail nails into a wall with this thing. I should have read closer that this was a half a pound. I probably should have ordered a bt20 to convert to a wrist light.

The light has the output I like, even beam pattern. I am certain that a two 18650, with fenix driver, is the only way to step up meaningfully from the 150 lumen over 8 to 10 hour runtime, needed for a workday. I was surprised that the color was so neutral, even compared with the hp11.
'
I think a better design would be a lighter grade of aluminum, an xpg2 with a head no bigger than the hp11. I would be happy with a high of 365 lumens with same current draw as now. Loose the high and half or more of the beef.

I even think the hp20 should have a 2 18650 option.

Well I finally think I got a design. I got a left handed ace wrist brace (all flexible) with glue and elastic and velcro, got a reasonable wrist light. Though probably not as practical as my single 18650 xpg2 from Hank, but there, the weakness is the driver (pwm means 90 lpw) and the orange peel reflector.
 
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StinkEye

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Mar 11, 2013
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I'm looking for my first good light and this one is high on the list right now. I am considering others as well and making a list as I learn about them. The RC15 looks interesting as do some Eagtac models.
Question: Is the big drop from Turbo mode at 860lm and High at 300ish typical?
Thanks for the great information on this light. I hope to make a decission soon.
 

selfbuilt

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Question: Is the big drop from Turbo mode at 860lm and High at 300ish typical?
Perception-wise, it's not as great as the numbers make it seem. We perceive output in a non-linear way, so the difference won't seem so huge to you in practice.

:welcome:
 

StinkEye

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Perception-wise, it's not as great as the numbers make it seem. We perceive output in a non-linear way, so the difference won't seem so huge to you in practice.

:welcome:

Thanks for the welcome.
So what you are saying is that even though there is a greater than 50% drop in lumens (output?), it is still quite bright and it appears to be something less than the 50% decrease. Is that correct? Does power consumption follow a linear correlation to the lumens - ie 50% decrease in lumens = 50% decrease in battery consumption?
 

selfbuilt

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So what you are saying is that even though there is a greater than 50% drop in lumens (output?), it is still quite bright and it appears to be something less than the 50% decrease. Is that correct?
Yes, that is right - the difference will not seem as great to you, relatively speaking (due to how we perceive brightness).

Does power consumption follow a linear correlation to the lumens - ie 50% decrease in lumens = 50% decrease in battery consumption?
No, emitters are more efficient when driven to lower levels, so output to power consumption is not linear. You can infer this from my runtime graphs - the TK35 is a little less than half as bright on Hi compared to re-started Turbo, but runs for more than three times as long on the same batteries. For that matter, output to current relationship is not perfectly linear either (although it is close enough over small changes to be considered reasonably so). If you check the manufacturer specification data sheets for any emitter, you will typical see sample curves.

But in the larger scheme of things, it is definitely our relative perceptions that are far more non-linear. They actually follow a power relationship, as I describe in this post: http://www.candlepowerforums.com/vb/showthread.php?309976&p=3589726&viewfull=1#post3589726
 
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RemcoM

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Yes, that is right - the difference will not seem as great to you, relatively speaking (due to how we perceive brightness).


Not exactly - the output to current relationship is not perfectly linear (although it is close enough over small changes to be considered reasonably so). If you check the manufacturer specification data sheets for any emitter, you will typical see sample curves.

But in the larger scheme of things, it is definitely our relative perceptions that are far more non-linear. They actually follow a power relationship, as I describe in this post: http://www.candlepowerforums.com/vb/showthread.php?309976&p=3589726&viewfull=1#post3589726

Hi,

Your TK35 has only 20000 cd of beam intensity, while manufacturer says 35,000 cd , thats a bit dissapointing.

1 How come, that it is so less?

2 You have, or had, also the Fenix TK41, or the TK60?

Much more throw.

What is your opinion about the TK41, and the TK60?
 

selfbuilt

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Your TK35 has only 20000 cd of beam intensity, while manufacturer says 35,000 cd , thats a bit dissapointing.
1 How come, that it is so less?
Again, this is an older review, published almost two years ago. In that time, Fenix has updated its emitters. It's current standard TK35 XM-L U2 is reported by Fenix to have 29,000 cd.

Also, I was using an inexpensive lightmeter at the time this review was completed. My more recent reviews have results using a NIST-certified lightmeter, which typically increased the measures of most my lights. See for example:

750N1-FL1-Summary-2x.gif


But again, this measure is from a two-year TK35 sample.

2 You have, or had, also the Fenix TK41, or the TK60?
No, I haven't reviewed those lights.
 
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BringerOfLight

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Hi,

Your TK35 has only 20000 cd of beam intensity, while manufacturer says 35,000 cd , thats a bit dissapointing.

1 How come, that it is so less?

My TK35 with XML T6 (1 year old) comes in at 36000cd (measured at 5m with calibrated spectrometer). My reflector looks a lot smoother than the picture from the review.

Keep in mind that tiny differences in LED positioning can make a giant difference in throw. So I think selfbuilt's sample doesn't have perfect reflector and the LED alignment is a bit of.
 

degarb

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Hi,

Your TK35 has only 20000 cd of beam intensity, while manufacturer says 35,000 cd , thats a bit dissapointing.

1 How come, that it is so less?

2 You have, or had, also the Fenix TK41, or the TK60?

Much more throw.

What is your opinion about the TK41, and the TK60?


The stated is 29,000. I am reading 28,000. Not a fancy meter. And U2 bin. This is normal since bin's vary 5% or is it %15.

The 360 lumen rating: 12,000 ccd on my meter.

The 120 lumen rating: 4,100
 
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theOS

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Hi , what batteries do you recommend for the tk35 (Panasonic 3100/3400mAh; efest 3100mAh; Ampmax 3100mAh; Ultrafire 3100mAh) ?

I totally recommend this flashlight , i use it every night!
 

selfbuilt

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Hi , what batteries do you recommend for the tk35 (Panasonic 3100/3400mAh; efest 3100mAh; Ampmax 3100mAh; Ultrafire 3100mAh) ?
That's really a question for the electronics and batteries subforum here. I don't have any specific recommendations for batteries.
 

can'townenough

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Nov 21, 2013
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Thank you self built for you very excellent review of this light which I actually have purchased two of since I liked mine alot and I needed a present for my mom. When I purchased the second one it was when they had just changed from the T6 to a U2 adding another 40 lumens drastically reducing the price of the older version at the time around 65-75. It doesn't compare with the nitecore TM11 as far as output per ounce. I do like that it has the sos setting unlike the TM11.
 
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