# Review of Fenix TK41, with measurements and outdoor beamshots



## HKJ (May 15, 2011)

[SIZE=+3]Fenix TK41[/SIZE]












This light is the 3. light with 8 AA cells from Fenix, this time the light is using the XM-L led (The other where MC-E and 3xXP-G). The light has four brightness settings and two flashing settings, controlled with two electronic side switches. The light is made of aluminum with hard-anodized (Type 3) finish. 














The light is supplied in a plastic box with cardboard wraparound. 






The box contains the light, a lanyard, two spare o-rings, a warranty card and the manual.









The light has a large smooth reflector with a XM-L led in the center, as can be seen in the beamshots this reflector does give the light a very good throw.









The head has some flat surfaces that prevent the light from rolling. Around the led there is a heatsink to help radiate up to 11 watt of heat.






Behind the heatsink is the two switches, one for on/off and selection between steady light or flashing modes, the other switch to select brightness level or flashing mode. The switches are electronic, this means that the light will have a small standby current drain.









The head has a good quality thread with an o-ring for connect to the body. The backside of the head has the connection to the battery carrier, this is a solid construction with a circuit board that is reinforced with metal where the springs from the carrier connects.






The body is covered with a checkered pattern and on the squares there are small ridges, this gives a good grip on the light.












The tail has holes for the lanyard and allows tail standing of the light. Inside the tailcap there is no connections, the body of this light does not carry any current. The tailcap is mounted with good quality square threads. There is also an o-ring to make the light weatherproof.










The light uses a battery carrier for 8 AA batteries. They are connected as two strings of 4 batteries.









The carrier uses springs for connection to the light, both + and - are at the front end, the back of the carrier does not carry any power.









The carrier has mechanical polarity protection at the plus pole.






Here are all the parts of the light.


This upgrade to the TK40 has higher output and is more focused, making it a good thrower. The side switches is easy to use in an underhand grip and Fenix has also reduced the standby draw to a more acceptable level. With these improvements I believe it is a good update and a good light for people that want to use standard batteries (instead of LiIon).



[SIZE=+2]Technical specification and measurements[/SIZE]





The light can work with alkaline, lithium and NiMH batteries and needs 8 cells (Fenix does approve of lithium in this light and recommend NiMH).

Measured size and weight:
Length: 215 mm
Diameter: 40 to 62.6 mm
Weight: 527 gram with eneloop

The light uses a Cree XM-L led.






In the above table I have collected all modes. I have also included off as a mode, because the light uses a small amount of power. All the estimated runtimes are with eneloop batteries. The estimated lumen are scale from the specified maximum and shows that high and med settings are close to specification. The brightness is a relative measurement from a lux meter or a light sensor (For flashing modes).
All the values are measured at 4.8 volt.






The voltage sweep shows a light with very good stabilizing down to 3.7 volt. The "funny" looking curve at 3.7 volt is my equipment that has some problems with the fast reduction in current draw.






With high the stabilization works down to 3.3 volt and my equipment does also has some problems here.






Medium stabilizes down to 3 volt.






Low can stabilizes down to 2.7 volt.







The good stabilization gives a very flat runtime curve, when the batteries are nearly empty the light drops out of stabilization and can keep a low brightness for a long time.






The strobe changes between 6.8 hz and 15.8 hz with two seconds of each.






The sos uses a 0.35 sec unit and it takes 11.6 second to transmit one sos, the pause between is 2.5 second.


[SIZE=+2]Comparison to other Flashlights[/SIZE]

Fenix TK40, Fenix TK41, Fenix TK45











Fenix LD40, Sunwayman M40A, Olight M31 Triton











For the full comparison to other lights with graphs and beamshots see here


.


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## kj2 (May 15, 2011)

Thanks


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## kj2 (May 15, 2011)

How do you know, how much the heatsink can handle?


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## EngrPaul (May 15, 2011)

Thanks for the excellent review. 

It's a shame that the main (+) spring has the cut end of the coil as the high spot. It's digging in and removing all the gold off the mating face on the head. With all that pretty flash gold over everything, it's a shame that it's already gone from where it's needed the most.

I would consider a slim head version of this light, with the additional flood that comes with it. No molded plastic like the other Fenix, let the body be the heat sink. Batteries need to release heat too


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## selfbuilt (May 15, 2011)

Nice review HKJ, as always - very clear and concise, with tons of useful data and observations. :thumbsup:

Sounds like a winner overall. I never picked up the TK40, since I like a bit of throw in my high powered lights. And glad to see they've reduced the standby current to something similar to the TK45 (well, twice as high here, but since the batteries are 4x2 instead of 8x1, that works out to a similar 3.5+ years).



EngrPaul said:


> It's a shame that the main (+) spring has the cut end of the coil as the high spot. It's digging in and removing all the gold off the mating face on the head. With all that pretty flash gold over everything, it's a shame that it's already gone from where it's needed the most.


Hmm, good catch. Part of why I like those solid metal reversible carriers that Sunwayman uses.


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## Samy (May 16, 2011)

I think i'm just about ready to get one of these, but i need something that doesn't have a 'tunnel vision' spot. I need need something super bright with plenty of spill/flood around it too. Does the TK-41 have plenty of spill? Photos never do lights justice. Otherwise i might wait for the TK70 

cheers


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## Mr Floppy (May 16, 2011)

Is that your hand? It's massive, It dwarfs the TK41.


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## HKJ (May 16, 2011)

kj2 said:


> How do you know, how much the heatsink can handle?



I know how much it has to handle, the light uses up to 11 watt (But I did not subtract the power going out as light, it is probably 2 to 3 watt).



EngrPaul said:


> It's a shame that the main (+) spring has the cut end of the coil as the high spot. It's digging in and removing all the gold off the mating face on the head. With all that pretty flash gold over everything, it's a shame that it's already gone from where it's needed the most.



The gold layer get scratched off on the outer ring too. I do not believe that this is a problem, there is a thick layer of metal, the springs has a decent pressure and any oxidation will be removed when screwing the light together.




Samy said:


> I think i'm just about ready to get one of these, but i need something that doesn't have a 'tunnel vision' spot. I need need something super bright with plenty of spill/flood around it too. Does the TK-41 have plenty of spill? Photos never do lights justice. Otherwise i might wait for the TK70



For lots of spill you need the TK45. The TK41 has some spill, but I can hardly say if it is enough for you.



Mr Floppy said:


> Is that your hand? It's massive, It dwarfs the TK41.



Yes, it is my hand, the same as I uses in all my recent reviews.  I believe the size is about average around here.


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## candle lamp (May 16, 2011)

Great review and thanks a lot. HKJ

TK41 looks very nice! 

The current on turbo mode seems 2.8A. Is it right?
Is the screw of the head side squre threads too? 
Do you notice the batteries-rattling sound in the body tube?

Thanks in advance.


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## HKJ (May 16, 2011)

candle lamp said:


> The current on turbo mode seems 2.8A. Is it right?



The maximum current it draws from the batteries is 2.8 A (Thats 1.4 A for each bank), but most of the time it will be considerable less (See red line on Turbo chart).
The led is probably feed with 2.8A.



candle lamp said:


> Is the screw of the head side squre threads too?



No.



candle lamp said:


> Do you notice the batteries-rattling sound in the body tube?



I did not notice it, but then I did not try shaking the light.


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## EngrPaul (May 16, 2011)

HKJ said:


> The gold layer get scratched off on the outer ring too. I do not believe that this is a problem, there is a thick layer of metal, the the springs has a decent pressure and any oxidation will be removed the screwing the light together.


 
I agree with you on this. Because of decent spring force, the carriage would probably work just as well if it was nickel plated only and had no gold on it. 

Due to cost, the gold is most likely a soft flash, not a wear resistant hard gold. Gold is commonly used on the PCB to protect the solderability of the nickel underneath the pads (ENIG), not for contact performance. I see there is some soldering done on the carriage springs as well. 

Can't deny it was a good choice for looks. I wish the ends of spiral springs in flashlights would generally be less damaging to cells and terminals. It seems it's more cost effective to leave the cut end of the coil spring at the tip. I will be on-site at a spring manufacturer tomorrow and I'll ask them about end conditions of spiral springs.

As a flashlight owner, if I see deep scarring on terminals or cells, I will deburr or re-bend the spring as needed.


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## bbb74 (May 16, 2011)

I know this is going to come across as a very noob question and I'm going to regret asking it, but I'm confused.

In turbo it draws 2.8A, or 1.4A per bank of 4 cells. Doesn't this mean it draws 350mA per cell (1.4/4), so it should last >5 hours with eneloops? Obviously I'm making a mistake here because it doesn't in fact last that long but can't figure out what I'm doing wrong...


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## HKJ (May 16, 2011)

bbb74 said:


> I know this is going to come across as a very noob question and I'm going to regret asking it, but I'm confused.
> 
> In turbo it draws 2.8A, or 1.4A per bank of 4 cells. Doesn't this mean it draws 350mA per cell (1.4/4), so it should last >5 hours with eneloops? Obviously I'm making a mistake here because it doesn't in fact last that long but can't figure out what I'm doing wrong...


 
Each bank is 4 cell in series, this increases voltage but keeps current the same.
With banks in parallel the voltage stays the same, but the current increases.

A simple example with two cells, each 1.2 volt 2000mAh:
In series: 2.4 volt, 2000 mAh
In parallel: 1.2 volt, 4000 mAh



And again: The light does not draw 2.8 ampere all the time, but more like 2.2 ampere in average.


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## bbb74 (May 16, 2011)

Ah thanks. So each individual cell is putting out 1.4A at ~1.2v hence the runtime. For some reason I figured that I needed to divide the current by the number of cells providing it, but now I get it. Now if I could delete my post...


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## kj2 (May 16, 2011)

EngrPaul said:


> Thanks for the excellent review.
> It's a shame that the main (+) spring has the cut end of the coil as the high spot. It's digging in and removing all the gold off the mating face on the head. With all that pretty flash gold over everything, it's a shame that it's already gone from where it's needed the most.
> I would consider a slim head version of this light, with the additional flood that comes with it. No molded plastic like the other Fenix, let the body be the heat sink. Batteries need to release heat too



On my TK35, there a some spots where the gold is gone. It still works, but it's a shame that it comes that easily off.


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## igoman (May 16, 2011)

Thanks for the review.


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## stickx (May 16, 2011)

In a real pinch, would it run on 4 cells in one string with reduced run time on low or medium? I assume that high or turbo would be too much current draw.


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## HKJ (May 16, 2011)

stickx said:


> In a real pinch, would it run on 4 cells in one string with reduced run time on low or medium? I assume that high or turbo would be too much current draw.


 
Yes, turbo will probably also work with eneloop (This mostly depends on the springs in the battery carrier).


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## MissingLink (May 16, 2011)

HKJ said:


> Yes, turbo will probably also work with eneloop (This mostly depends on the springs in the battery carrier).


 
Have tried this and turbo still works on 4 AA's (Eneloops).


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## Mr Floppy (May 17, 2011)

HKJ said:


> Yes, it is my hand, the same as I uses in all my recent reviews.  I believe the size is about average around here.


This is only one where I have a yardstick to measure your hand by. If I hadn't already seen the size of a TK41, I'd say it was a compact torch.


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## candle lamp (May 17, 2011)

HKJ said:


> Each bank is 4 cell in series, this increases voltage but keeps current the same.
> With banks in parallel the voltage stays the same, but the current increases.
> 
> A simple example with two cells, each 1.2 volt 2000mAh:
> ...


 
Therefore Is the input voltage totally 4.8V (4000mAh capacity) in case of using Eneloop Ni-Mhs? 

Do we call it 4S2P?

Thanks for your answer to my previous question.

Best regards,


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## HKJ (May 17, 2011)

candle lamp said:


> Therefore Is the input voltage totally 4.8V (4000mAh capacity) in case of using Eneloop Ni-Mhs?



Yes. Just remember that NiMH has a nominal voltage of 1.2 volt, a freshly charger NiMH is above 1.4 volt.




candle lamp said:


> Do we call it 4S2P?



Exactly.


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## candle lamp (May 17, 2011)

Thanks a lot for your time. HKJ 

One more question please.

How about the batterires connection for TK40, TK45?

Are the both lights 8 cells in series(=8S)? 

I could get the above assumption from your _TK45 review's table_.


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## HKJ (May 17, 2011)

candle lamp said:


> How about the batterires connection for TK40, TK45?
> 
> Are the both lights 8 cells in series(=8S)?



TK40: 4S2P
TK45: 8S


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## Sharpy_swe (May 17, 2011)

As always :goodjob:

Your reviews are always top notch!


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## Sunflash (May 17, 2011)

Sharpy_swe said:


> As always :goodjob:
> 
> Your reviews are always top notch!


 
+1
good job.


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## bbb74 (May 19, 2011)

Thankyou for the review. Out of curiosity I was looking at the cree xm-l specs.

The XM-L maxes out at a max of 3A and a forward voltage of ~3.35V = ~10 watts. Your graphs show the TK41 maxing out around the ~10.5 to 11 watts mark, so after subtracting driver loss, it appears the led is being driven at about 100%.

Note Cree say: "Cree currently recommends a maximum drive current of 1500 mA for XLamp XM-L white in designs seeking the ENERGY 
STAR* 35,000 hour lifetime rating (≥ 94.1% luminous flux @ 6000 hours) or 25,000-hour lifetime rating (≥ 91.8% 
luminous flux @ 6000 hours)."

Cree also say that at 3A, the XM-L will be at 325% of the rated luminous flux (which is 280-300 lumens @ 700mA for the T6 bin) so 910 to 975 lumens at 3A. Given that Fenix say 800 lumens for the TK41 does that sound right? Only a ~15% drop in output from emitter lumens to ansi lumens??

Again must be something wrong with my maths... but maybe not as xm-l peak out a touch above 1000 lumens with a U2 bin?


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## HKJ (May 19, 2011)

bbb74 said:


> Note Cree say: "Cree currently recommends a maximum drive current of 1500 mA for XLamp XM-L white in designs seeking the ENERGY
> STAR* 35,000 hour lifetime rating (≥ 94.1% luminous flux @ 6000 hours) or 25,000-hour lifetime rating (≥ 91.8%
> luminous flux @ 6000 hours)."



Flashlights are not designed for energy star ratings.



bbb74 said:


> Cree also say that at 3A, the XM-L will be at 325% of the rated luminous flux (which is 280-300 lumens @ 700mA for the T6 bin) so 910 to 975 lumens at 3A. Given that Fenix say 800 lumens for the TK41 does that sound right? Only a ~15% drop in output from emitter lumens to ansi lumens??


 
You calculations looks fine to me and I agree with you that a getting 85% of the light out the front is a very impressive feat (If they use the T6 bin). 
Fenix might not even drive the light at 3A, if you look at my voltage sweep, it peeks at 2.8A. This does not have to be the led current, but probably it is.


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## bbb74 (May 19, 2011)

HKJ said:


> Flashlights are not designed for energy star ratings.


I know I know, but am wondering how long a tk41 will actually last if its always in turbo. I'm thinking of getting one but would hate the guilty feeling when going exploring for a few hours in turbo 



> You calculations looks fine to me and I agree with you that a getting 85% of the light out the front is a very impressive feat (If they use the T6 bin).
> Fenix might not even drive the light at 3A, if you look at my voltage sweep, it peeks at 2.8A. This does not have to be the led current, but probably it is.


 That 2.8A was at a voltage of about 3.7v or something though right, so at the xm-l's max forward voltage of 3.35v the current could be around 3A?


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## DavidD (May 29, 2011)

I read that the lux of the TK41 on Turbo is approximately 55,000. I am wondering how that transfers down to the lower levels. Is the formula linear (cross multiply & divide) or is there a different formula?

Does 55,000 @ 800 Turbo translate to:
23,031 @ 335 High? (335*55,000/800)
7,425 @ 108 Medium? (108*55,000/800)
688 @ 10 Low? (10*55,000/800)

For those familiar with the Streamlight ProPolymer Luxeon 4AA, I believe it was about 3,000 lux @ 42 lumens, give or take - and considered a good thrower at those levels. Adding in 1 more comparison to the above list...

2,888 @ 42 ProPoly Level (42*55,000/800)

Does this indicate that it is about the same degree of thrower as the ProPoly (just able to go a WHOLE lot brighter)?

-- just trying to get a handle on the throw at the lower levels...
David


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## HKJ (May 31, 2011)

DavidD said:


> I read that the lux of the TK41 on Turbo is approximately 55,000. I am wondering how that transfers down to the lower levels. Is the formula linear (cross multiply & divide) or is there a different formula?
> 
> Does 55,000 @ 800 Turbo translate to:
> 23,031 @ 335 High? (335*55,000/800)
> ...



That is correct.




DavidD said:


> For those familiar with the Streamlight ProPolymer Luxeon 4AA, I believe it was about 3,000 lux @ 42 lumens, give or take - and considered a good thrower at those levels. Adding in 1 more comparison to the above list...
> 
> 2,888 @ 42 ProPoly Level (42*55,000/800)
> 
> Does this indicate that it is about the same degree of thrower as the ProPoly (just able to go a WHOLE lot brighter)?



Not really, there are many beam shapes that will have the same lux at the same lumen level. You can have a very small hotspot and lot of flood or you can have a large hotspot with no flood and anything in between. 
i.e. due to the higher lux the TK41 will throw much further than the ProPolymer, but does not necessary have the same beam shape.


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## ScaryFatKidGT (May 31, 2011)

Like the beam shots THX! wish you would of put in a TK35. Is the LD40 really that dull? and the TK45 is all flood?


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## HKJ (May 31, 2011)

ScaryFatKidGT said:


> wish you would of put in a TK35. Is the LD40 really that dull? and the TK45 is all flood?



Just click on the picture with all the lights and you will get many more beamshots that includes a TK35.
The LD40 is not dull, but it is less than half the lumen of the TK40/TK41/TK45 lights. TK45 is not all flood, but it is much more flood than than TK41.


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## AMD64Blondie (Jun 1, 2011)

Great.. I already own a TK40 and now you're tempting me again? Sigh...


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## burpee (Jun 1, 2011)

I really love all the great information posted here. And I'm about to pull the trigger on a TK41 purchase. But I'd like to hear whether someone who has already collected many remarkable torches whether I should just go ahead and make the move into flashlights using protected 18650 cells. I already own 40 or fifty AA NiMH cells and various chargers. 

How many of you have 2x18650 torches that have nearly the throw of the TK41? Can I get a torch, charger and cells for about $150 US? Don't mean to warp the thread, just asking?


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## Fern (Jun 2, 2011)

Hi HKJ and thanks for the review.

I recently purchased a TK41 and have a question regarding the beam profile.

My sample has a dark area where the hot spot should be which is encircled by a very bright ring before transitioning into the corona/spill.

This is ONLY noticeable beyond a distance of 4-5 meters. Any distance under that and the hot spot looks a normal solid white.

Here's a link to a video clip I took showing the effect:

http://www.mediafire.com/?qmc2mi2tpha07y2

This beam shot was taken at 20 meters.

Please note that the dark hot spot/bright ring effect was difficult to capture on camera and is much more apparent and obvious to the naked eye.

Does your TK41 sample exhibit this beam pattern?

I would like to establish if this is typical or if I have a defective unit. I have emailed Fenix but have received no response yet.

Feedback appreciated from any other TK41 owners.


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## trooplewis (Jun 3, 2011)

No donut hole in my hotspot, but my emitter is off-center and that may be why.


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## Fern (Jun 3, 2011)

Hi trooplewis thanks for responding.

My emitter is perfectly centered and so is my donut hole :shakehead

What distance have you checked your beam? As I mentioned this artifact only shows up at ranges exceeding 4-5 meters, and is very obvious even against targets such as foliage, textured surfaces etc. Definitely noticeable against a smooth wall.


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## Red-T (Jun 5, 2011)

My TK41 shows a similar pattern: very close (around 10 cm) a dark clover-shaped center, beyond that fairly smooth. At larger distances the hotspot has a more yellowish center with a brighter and bluish outer ring.


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## burpee (Jun 5, 2011)

> This beam shot was taken at 20 meters.
> Please note that the dark hot spot/bright ring effect was difficult to capture on camera and is much more apparent and obvious to the naked eye.
> Does your TK41 sample exhibit this beam pattern?
> I would like to establish if this is typical or if I have a defective unit. I have emailed Fenix but have received no response yet.
> Feedback appreciated from any other TK41 owners.


I just received my TK41 yesterday and by no means any expert. However, I can tell you that I do indeed see the "center hole" effect, although I couldn't see it in your video.
My TK41 emitter is perfectly centered any for anyone FYI - perfect switch operation every click.
I pointed my TK41 at a white wall 3 or 4 meters and at first glance did not notice the "hole effect." As I moved forward and away from the wall I can see the "center hole" effect appear and disappear in the hot spot. This lightening and dimming of the center of the hot spot is most definitely observable. Its not all illusion. 

I doubt this pattern can be described as a defect. Like yourself, I guess the next thing I would want to do is have some one else stand beside me and substantiate the changing nature of the hotspot in conjunction with my own perception. In addition, I wonder if the color of the wall or other factors will amplify or cancel this effect.

Hey I reviewed your video again - and now I see the effect - could you try holding the hotspot steady on the door and walk toward and then away -I think you'll see the "change" I describe.


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## Fern (Jun 5, 2011)

Red-T - at very close range the dark clover-shaped center is there on mine also. There are various colored rings in the spill/corona as range is increased noticeable on white wall especially but I believe this is just typical of a smooth reflector.

burpee - The reason I was moving the light around was to make it easier to see the donut hole and ring effect. It's just not anywhere near as distinct in the video as it to the naked eye. It is obvious regardless of what object the light is illuminating, that's why I noticed it immediately. I understand what you mean about holding the hot spot steady then moving back and away, I tested this several times with a friend to check if I was imagining it 

As I mentioned it was quite difficult to capture the effect on camera. Still shots were impossible because the reflected light was too great even on medium level and the hot spot looked completely full, white and 'normal' regardless of camera settings/setup and target surface.

That's why I switched to video.

I am very concerned this beam pattern is abnormal and will affect throw negatively. I have still not received a response from Fenix regarding this matter.


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## burpee (Jun 6, 2011)

Well I don't know jack-squat about light, physics or flashlights, but I know what "bright" and "throw" mean in torch-speak. And I can tell you right now -as far as AA powered lights goes - the TK41 is spectacular.

I'll speculate the "aberration" surrounding uneven patterns near the hot-spot have to do with slightly different wave-lengths of light arriving at the given surface in or out of phase, cancellation maybe?? (this at least explains why the pattern would change with distance)

Now I want to find the same performance in a 2x18650 torch. But if anyone wants an "AA" powered light the TK41 is your answer.


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## xoomercom (Jun 8, 2011)

I already have the TK 40, and TK45 (missus loves it), I just ordered the TK 41. 

Not much to say other than I love the fenix products. I'm impressed mostly with quality and output. Not to mention that I require AAs. I prefer the two button UI approach vs single clicker at the end. I'll post my take on it when it arrives.


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## AusKipper (Jun 8, 2011)

bbb74 said:


> I know I know, but am wondering how long a tk41 will actually last if its always in turbo. I'm thinking of getting one but would hate the guilty feeling when going exploring for a few hours in turbo


 
Even if it "only" lasts 25,000 hours because your using it in Turbo all the time, thats still about 3 years continuous 

Something else will break by then (probably the switch) anyway.

I wouldn't worry about it.


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## bbb74 (Jun 9, 2011)

AusKipper said:


> Even if it "only" lasts 25,000 hours because your using it in Turbo all the time, thats still about 3 years continuous
> 
> Something else will break by then (probably the switch) anyway.
> 
> I wouldn't worry about it.



I have the same question  I've read Cree's lumen maintenance guide (which doesn't really cover XM-L's) and temperature (particularly ambient (the temp in the air around the led)) seems to be the biggest killer. I have to think when you drive the tk41 at 10 and a bit watts, that its going to be getting very hot inside when you compare it to a larger light fitting with lots of fins and stuff and that will reduce the life. I'm not sure what the life will be though... Would be curious to know what Fenix say about it, and how they've designed it to keep the led as cool as possible and what temps they've designed it to maintain.


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## chenko (Jun 10, 2011)

Thanks for the great review, nice and useful information here! I just got my TK41 yesterday, it is superb and throws like no other lights I have experience of. It will be fun to amaze friends with it. My sample has good tint tough, some green is only visible in the hotspot's corona in the lowest setting, other settings all show a quite good cool white tint with a very slight bit of purple, which makes for a better cool type of tint overall. I'm kind of a tint snob, if those ever exist, and I usually only get flashlights in neutral or warm tint, but this tint seems acceptable to my eyes (if I don't directly compare to neutral ones, of course).


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## todd.krock (Jun 10, 2011)

Fern said:


> Hi HKJ and thanks for the review.
> 
> I recently purchased a TK41 and have a question regarding the beam profile.
> 
> ...



I got my TK41 about a week ago. I notice the dark hot spot as you describe it as well. Please report back what Fenix has to say. Other then that this light is pretty darn awesome. The light still puts out and the ring is more of an annoyance then anything. But im sure it does effect the throw. Granite I'm an old maglight user myself, but WOW i guess anything would be brighter!


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## HighLumens (Jun 11, 2011)

post deleted


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## Sinsear (Jun 11, 2011)

I recently received my TK41 from BatteryJunction. I am noticing a very green ring around the hotspot on all brightness settings. In addition, I'm also noticing the doughnut effect on hotspot, even at considerable distance (it's obvious that there's going to be a doughnut effect when shining at a very close object, but I'd expect that to go away after 2 or so meters). Instead, at long distances, you can definitely make out that the center portion of the hotspot is less bright than the edges of the hotspot. FWIW, I also think that my LED is centered perfectly (although I don't think I've seen a flashlight that wasn't). Should I return my flashlight and exchange it out? I think the most bothersome aspect is the fact that there's a very defined green ring around the hotspot.


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## louieg (Jun 11, 2011)

Waiting on my TK41 will let you know about green tinge and dark hot spot.


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## burpee (Jun 16, 2011)

I was out "testing" my TK41 last night on bicycle trails in southern Illinois - no lights near area of testing. This map - shows where I could light up a 10 inch by 30 inch highway info sign mounted above a tunnel that runs under IL route 4. According to this mapping software_ the TK41 was "throwing" almost 1 mile!_ It took almost 4 minutes to ride up to the sign.

Click black and red "checker" for map notes.


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## Nyctophiliac (Jun 16, 2011)

burpee said:


> I was out "testing" my TK41 last night on bicycle trails in southern Illinois - no lights near area of testing. This map - shows where I could light up a 10 inch by 30 inch highway info sign mounted above a tunnel that runs under IL route 4. According to this mapping software_ the TK41 was "throwing" almost 1 mile!_ It took almost 4 minutes to ride up to the sign.
> 
> Click black and red "checker" for map notes.



That's a lot of throw! Do you simply stop and try out the light, or have you found a way to mount it on your bike? Any info gratefully received as I have been trying to mount my TK45 for ages and Duck tape seems to be the only option, but it ain't pretty! Or quick release!!


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## samgab (Jun 16, 2011)

Nyctophiliac said:


> That's a lot of throw! Do you simply stop and try out the light, or have you found a way to mount it on your bike? Any info gratefully received as I have been trying to mount my TK45 for ages and Duck tape seems to be the only option, but it ain't pretty! Or quick release!!


 
Have you ever heard of, or tried, Twofish Lockblocks? I figure that even if you have to replace the velcro tape with a longer piece it could be jiggered to do the trick... 
Also, I've found that even when pointing a fairly faint flashlight at reflective signs, they light up from very far away. But a mile is still impressive!


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## todd.krock (Jun 16, 2011)

todd.krock said:


> I got my TK41 about a week ago. I notice the dark hot spot as you describe it as well. Please report back what Fenix has to say. Other then that this light is pretty darn awesome. The light still puts out and the ring is more of an annoyance then anything. But im sure it does effect the throw. Granite I'm an old maglight user myself, but WOW i guess anything would be brighter!


 
Ok, I reached out to Fenix myself with a few beam shot pics and here is the response I received.

"I fully understand the phenomenon you mention according to the picture, this is normal phenomenon, because the light generated by the LED is not all reflected by the reflector, some is not reflected, if reflected by the reflector, the light brightness will be high, so the center beam which is not reflected seems a little darker comparatively.

This is common, and won't affect the normal use at all, this can be proved during your actual use in future." 

Not sure I like the answer, but it is an answer none the less.


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## burpee (Jun 17, 2011)

> This is common, and won't affect the normal use at all, this can be proved during your actual use in future."


All lights that use a reflector will produce an uneven pattern at some point. The only way this could be avoided would be to have the reflector "meet" the very edge of the LED where light is generated, and even then you might get some uneven intensity.



> Have you ever heard of, or tried, Twofish Lockblocks? I figure that even if you have to replace the velcro tape with a longer piece it could be jiggered to do the trick...


I made my own mount out inner tube rubber.

The trick is to fashion two rubber supports that form a "cradle" and then use additional rubber strips as rubber bands. I use two strips for security and firmness. I was using the TK41 on an unlit trail 30 miles east of Saint Louis. I could notice one "object" reflecting in the distant horizon.

The trail goes straight under IL route 4 in concrete box culvert of a tunnel. There is a standard style green and white highway sign, green background, reflective white letters and border. The sign is mounted to a concrete wall - 15-20 feet above trail/ground. There is no competing light - anywhere nearby. 

I also use a folded piece of typing paper in the tube of the TK41 to dampen the battery carrier rattle. The TK41 was an experiment to examine how much "throw" is useful. It actually worked perfectly - although I doubt it is a good idea for mountain biking. The light was interesting to use because the spill was all out in front of me.

For a while I felt like I was in a locomotive cab lighting "rail trail."


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## Samy (Jun 17, 2011)

My TK41 arrived today. I took it to work to test it out. In the the darkish areas around buildings and street lights the TK41 did not appear to be an "awesome" light. It was certainly brighter than my 200 lumen edc, but the beam appeared too centered for built up areas.

When I came home I tested it out in the rural forest setting where I live. It's very dark with no street lighting and the TK41 simply came alive. Comparing to my other lights there was a huge difference. The TK41 doesn't seem to do very long distances but anything within 100-300 meters is lit up very well. I compared my Klarus ST20 (200 lumens) to the TK41 and holding them the same, the TK41 has an almost identical spill but much brighter. This wasn't noticeable in and around the buildings at work but out in the forest it was clearly evident. The TK41 has some decent spill. 

The other thing that suprised me is the excellent build quality and compact size. It does fit into my pockets 

Cheers


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## burpee (Jun 26, 2011)

I double checked the "throw" distance test i previously posted about. The TK41 will indeed light up a reflective sign a mile away. However, I do want to inform readers that most any light probably will do nearly the same. I tested the TK41 at the "medium" setting and found that there was a hint of reflection as well - at the 330 lumen rating.

It would be interesting for emergency professionals to have this same type of test performed - but use only the reflective surface of worker's safety vest as a reflector. In other words - test flashlights ability to find a piece of reflective clothing in a dark valley at 500 meters or more. That could be a useful test of beam character. Just saying....


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## Fatso (Jul 18, 2011)

Great review and some awesome pictures!!
How does the TK41 compare to the TK60? The specs. are almost Identical.


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## HKJ (Jul 18, 2011)

Fatso said:


> How does the TK41 compare to the TK60? The specs. are almost Identical.



I can not tell you yet. I already have the TK60 and have a TK70 on order, together with some other light. I plan on doing a "big lights" beamshot when they are arrives. I have not yet decided what ligths to include, but the TK41, TK60, TK70, SR51, SR90, SR91, SR92 and Blaster-NG will probably be included.


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## Fatso (Jul 18, 2011)

The big gun's!!
I am currently trying to decide on getting either the TK70 or SR91 and been deciding for over two weeks now and still have no clue. I know the SR90 is a lot brighter than the SR91 but the TK70 has the lower levels that might come in handy.
I'm looking for more throw than flood so I'm thinking the SR91 or is it really worth spending $200 extra for the SR90?


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## HKJ (Jul 18, 2011)

Fatso said:


> I am currently trying to decide on getting either the TK70 or SR91 and been deciding for over two weeks now and still have no clue. I know the SR90 is a lot brighter than the SR91 but the TK70 has the lower levels that might come in handy.
> I'm looking for more throw than flood so I'm thinking the SR91 or is it really worth spending $200 extra for the SR90?


 
The SR90 and SR91 I have are nearly same light output, but the SR90 has nearly twice the lux. This is not a big difference when you get out with them as can be seen in this beamshot or this beamshot.


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## Fatso (Jul 18, 2011)

Thanks to those beam shots I think I decided on the SR91. The SR90 looks to just have slightly brighter spill but a tighter hotspot. Basicly the SR91 should be easier to carry around than the SR90 and almost the same performance right?


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## HKJ (Jul 18, 2011)

Fatso said:


> Thanks to those beam shots I think I decided on the SR91. The SR90 looks to just have slightly brighter spill but a tighter hotspot. Basicly the SR91 should be easier to carry around than the SR90 and almost the same performance right?


 
Yes, but the SR90 has a bit more throw.


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## Fatso (Jul 18, 2011)

OK thanks for the awesome reviews.


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## Fatso (Jul 18, 2011)

Is the 90 really worth the extra $200 bucks over the 91? If I held them side by side is there a Noticeable big "WOW" difference while shining at 300 yards? Something is telling me to just buy the 90 instead of the 91 but I can't seem to press the confirm button yet.. LOL..

HELP!!!


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## monsieurmac (Aug 4, 2011)

*TK41 or ?? (for outdoor use mostly) *

Hi there,

I was looking at some of the reviews posted and was hoping someone could guide me in the right direction. I'm looking for a flashlight that could help me illuminate a wide area in a park as our yard backs onto it and I've had a few unwanted visitors this past week. Would the TK41 be a good fit for this purpose or would you recommend a different flashlight?

Post Merged into Review of Fenix TK41, with measurements and outdoor beamshots - Norm


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## Richub (Aug 4, 2011)

The TK41 is the best thrower of the three Fenix 700+ lumens lights.

So yes, that TK41 will light up those trespassers pretty well, and may even blind them too.


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## bbb74 (Aug 4, 2011)

I tried my tk41 out in my local park and it easily lit up the entire part of the park i pointed it at - there's no way anybody could hide even if I was half blind. It throws really well but it has quite a lot of very useable flood too. The park was about 100x100 meters.

As regards to blinding them, well I [very briefly] pointed the tk41 at my face in turbo mode (arms length away). Even though my eyes were very tightly screwed shut they couldn't cope with the light and would sting and tear up when I flicked the beam past my face very fast. It had the same effect on my wife at 5 meters range - too bright even with eyes closed tight. I tried it with my hand over my eyes, with my eyes closed, and it was still very bright and I could kind of see my hand


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## Fatso (Aug 5, 2011)

The TK41 looks like an awesome thrower. I bought the TK60 and the 40 is suppose to be the same. It lights the whole football field with ease and farther!


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## holeymoley (Aug 13, 2011)

Just getting around to reading this...great review! I've been looking for a good thrower and I think I'm sold. Maybe I'll pick one up next paycheck.


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## SamSpade (Dec 21, 2011)

Thank you for this review. Along with 2 other TK41 reviews I've seen here at CPF, this one convinced me to buy it ... my first non-budget LED flashlight. I have a collection of Maglite 2D LEDs, with the 1st gen Luxeon III from 4 years ago, to the current Cree XP-E emitters. Thought they were already awesome but realized through this forum that I'm actually ignorant of the current state of the art.

I'm a hobbyist electrical engineer. The graphs you showed were exceptional, and I credit Fenix for keeping Turbo mode regulation down to 3.7 V, or 0.925 V on average for the 4-series cells. That's the sign to immediately recharge the batteries. Using NiMh cells below 1.0 V for extended periods doesn't help with their lifetime, and there's a big chance some of them might have already reversed if the cells were balanced.

Thanks!


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## iron potato (Dec 30, 2011)

Drooling..... thanks for a great review.... TK41 sure is on my list for 2012


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## mr.lumen (Feb 6, 2012)

just got a tk41 and the emitter is off center. kind of disappointing from a high quality light manufacturer but oh well what can you do. no black hole in the hot spot.


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## Samy (Feb 6, 2012)

It won't make any difference, I have a fairly well centred led but glue on my reflector. It throws with awesome power...

Cheers


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## TEMPA (Feb 16, 2012)

Just got a TK41 today. Turned it on in our dark loungeroom and LOL'd at my wife saying "Are you f***ing for real?!?!? That thing's blinding!"

Just the reaction I was expecting because I thought the exact same thing a few minutes earlier when I turned it on!


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## bruintennis (Feb 16, 2012)

TEMPA said:


> Just got a TK41 today. Turned it on in our dark loungeroom and LOL'd at my wife saying "Are you f***ing for real?!?!? That thing's blinding!"
> 
> Just the reaction I was expecting because I thought the exact same thing a few minutes earlier when I turned it on!



LOL!!! that made me laugh!!!


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## qtn2x (May 18, 2012)

Thanks for the review. I ordered this one and can't be any happier. Very solid all the way.


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## peterkin101 (Jun 20, 2012)

I took a punt and purchased a TK41 which arrived about 2 hrs ago. Easily the best AA powered Torch I've ever seen. Great handling and a phenomenal beam. Only foible-the internal battery holder is AWFUL...cheap and nasty. Fenix ought to take a leaf out of LED Lensers book. Everything else though is utter perfection. Just enough modes, no silly 25 profiles or connecting to the Internet via 4G, WiFi or any of that rubbish. For the price I paid an extreme and utter BARGAIN!


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## UrbanLegend (Feb 16, 2013)

Bought one of these based on reviews. When my wife used it to walk our Boxer dog here in our rural 3-acre yard and adjoining woods/fields, she was AMAZED at its ability to light up the tree lines a quarter mile away on the other side of our neighbor's corn field. And that was only on the high setting! She turned it on Turbo setting, aimed it up at the night sky and marveled at the distance as the beam seemed to reach up almost to the stars!

After a quick tutorial on the tactical uses including the powerful, blinding strobe mode, she asked me to order two more... one to keep in her car and one at work. She works at an 18-acre museum with several buildings and often walks across the museum campus alone at night in the dark. I also got her a Maglight-D belt loop holder which fits the TK41 perfectly, so if she has to use both hands to unlock and open a door she doesn't have to set the light down in the rain or snow. Coupled with a high-end pepper spray, gun, she feels much safer! 

Thanks for the reviews and beam shots of this powerful light. Nice job!


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## Jash (Feb 16, 2013)

Yep, the TK41 is still a top light. I've had mine for over 18 months and it's seen a lot of use. It looks very second hand and beat up (been dropped onto concrete more than once). The switch covers seem to be holding up well and look only slightly worn, but with plenty of life left in them yet.

I charge the cells up about once a month. It's used mainly for walking the dog, although since I got the E50 it hasn't made it outside. I might relegate it to being the car light, replacing the Malkoff endowed 3D Maglite with it. The TK40 looks utterly obsolete now, compared to the E50 and TK41.



*edit* WOOHOO!!! Post #1111


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## bmwproboi05 (Apr 17, 2013)

Anyone have comparison to a ld41 and pd32UE. Wantting something that throws further than the UE


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## Labrador72 (Apr 18, 2013)

The LD41 will throw WAY further than the UE.
Not only it has a much bigger reflector which alone it would help throw further but it has over 55000 candelas against the "miserable" 6000 from the PD32 UE.
The PD32 is very bright for its size but as throw goes, it's nothing to write home about. Even my PD31 will throw a tad further than the PD32 UE!


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## drgt (Jul 15, 2013)

A switch should have been implemented to prevent slow battery discharge when the unit is stored away.
The manufacturer's recommendation that the head be unscrewed 1/2 turn is MISLEADING and simply NOT TRUE as it takes almost 2 turns to break contact.
If you leave the unit like that, it WILL NOT FIT in the plastic box it came in (unless you force it).

A wired battery caddy to cigarette lighter plug would have been a nice accessory!


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## greenskynz (Jul 18, 2013)

Any thoguhts on Fenix RC15?, in terms of lumens looks similar to TK41, but is more compact 160mm and look a bit more agressive almost like a tactical flashlight which would fit a holster. To me having a dedicated rechargable flashlight with a car charger might be a big plus especially in disaster situations when there is no power and in general there is no hassle with so many batteries. Thanks


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## Mojo Inc (Jul 27, 2013)

well this is why I joined wanted a good review of the light I am "NOW" going to buy. Thank you !!! Very helpful !!!


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## swockan (Nov 29, 2014)

Thanks for a great review!

My EA8 died on me (never Nitecore again) and I didn't like the step-down.

After reading your review I took the plunge and ordered the 900 version TK41. Hopefully it will arrive here to me in sweden from the states before christmas


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## NoNotAgain (Nov 29, 2014)

I've got two of the TK41's, a 860 and 900 lumen version. 

I also have more than 3 dozen high lumen lights, but for an all around light, the TK 41 is my go to light.


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## swockan (Dec 8, 2014)

Just got it in the mail!
First impression. I love it. 
Fits in the strap holder on my bag. Great output. A little rattlling noise from the battery holder when tighten down but not so much that it's annoying. And best of all, no timed step down on high. This will light up the dark north. Winter is coming.


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## NoNotAgain (Dec 8, 2014)

Two pieces of electrical tape around the holder will stop the rattle. Also makes it easier to keep the cells from squirting out while your loading the carrier.


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## DIBBS (Dec 14, 2014)

I think I'll take the plunge and purchase one of these. Several places have the L2 model (900lumens) @ around $100 for the aa version, 140 for rechargeables with charger. Any better deals out there?


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## swockan (Jan 22, 2015)

NoNotAgain said:


> Two pieces of electrical tape around the holder will stop the rattle. Also makes it easier to keep the cells from squirting out while your loading the carrier.



Thanks for the tip. This fixed the noise! 
However, I've seen the exended runtime kits for the TK75 but I have not seen any for the TK41? Have anybody tried putting the TK60 tube with two TK41 batteryholders or bought two TK41 and tried using the battery tubes and battery carriers together for exented runtime? 
I'm a little bit cheap to buy another TK41 and try it out before I know it works. 

Would be cool to have a 16xAA TK41 

EDIT: Seems like the threading on the TK41 tube makes it impossible to mount two together. But the TK60 tube could work, a little tight but 4 D batteries is the same size as two batteryholders for the TK41.


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## thermal guy (Mar 20, 2018)

Mr Floppy said:


> Is that your hand? It's massive, It dwarfs the TK41.



OMG I know this is an old thread but I just died seeing this post. I have a TK41 but in your hand it looks like a min mag😂😂😂


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