Author Topic: Fenix TK61  (Read 16410 times)

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Offline 18sixfifty

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Fenix TK61
« on: May 19, 2014, 01:10:00 AM »
I picked up a Fenix TK61 off of an evil bay seller the other day ($130 delivered in three days). It's an interesting light for sure. The head is huge on it so it throws. they did a good job designing the reflector. Very nice lightweight light for the size. I much prefer the TN31 anodizing though. The Fenix is kind of "slippery" feeling. Not what I expected anyway. But for such a large light it actually carries nice and the four batteries combined with lower amps will give it all kinds of run time.

The best part is that it really throws even with minimal amps it's a true super thrower. 175kcd I what I got on mine. Well that was after centering the emitter better. It came in slightly off center and was only at about 150kcd.

I like the UI on it. Just the standard two buttons one for On and Off and one for the modes. Four modes and then a hidden blinky. Good enough really although again not as nice as the TN31.

Taking it apart I was surprised to see how poor the heatsinking is on it. I can see why they don't push it harder. It has a small "pill" that sits on a shelf. There isn't a ton of contact there really, it is screwed down with two tiny screws and had some thermal paste under it. But not all the way around.

I de-domed the light and added some thermal paste including on the edge of the pill and around the bottom of the pill so now it's transferring heat to the body better.

It's a cool light but honestly if Thrunite makes a TN-32XL with a larger head but everything else the same it will blow this light away.

All that said, it's one heck of a thrower for the money. Even stock it's a pretty good thrower really. With just the simple de-dome it falls into the super thrower range with no problem at all. Plus it's going to run like a champ and do it all day long really. I might get around to ordering some resistors to do the resistor mod and increase the amps, but then again I might not. I like knowing I can run it on high as long as I like without worry and also being able to do so for a very long time.

It's a cool light and I'm glad I picked it up. I'm also glad though that I didn't end up selling my modded TN-31. The TN just feels like more of a light. 

Offline JohnnyMac

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Re: Fenix TK61
« Reply #1 on: May 19, 2014, 01:21:25 AM »
Thanks for the input on this light.  Spas and I were actually considering getting these since Vihn is getting about 620kcd after modding them.  They look like really impressive lights.  Kind of a bummer to think that the heatsinking is so poor.  I wonder how Vihn's modded versions will hold up with extended use.  I've never owned a Fenix light and this would be a cool one to have (I think).  You picked it up for a great price!

Offline MRsDNF

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Re: Fenix TK61
« Reply #2 on: May 19, 2014, 09:58:37 AM »
The beam must be like a laser with a head diameter of 96mm. Thats massive. With a runtime of over 4 hours on turbo shows that it cant be driven that hard. I assume the batteries are in parallel. l reckon that there is no question that you must fit an MTG-2 in it if the batteries are in series.
« Last Edit: May 19, 2014, 09:59:57 AM by MRsDNF »
When the big picture is to big, look for a point you can start at and build from there.

Offline 18sixfifty

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Re: Fenix TK61
« Reply #3 on: May 19, 2014, 09:46:17 PM »
It's not as much of a laser as I would have thought. It just does a good job because the hotspot is really tight. The flood is still rather large. There just isn't much of a corona/secondary hotspot. At a distance the hotspot really opens up too. I like the light a lot actually and I haven't run it for an extended time so maybe it can handle heat management better than I think but I would still be a little leery running it up to 5 or 6 amps.

The batteries are 2S2P I wouldn't put an MT-G2 in it though because of the heatsinking.

I wonder if Vihn adds any heatsinking. There is room for it.

Offline MRsDNF

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Re: Fenix TK61
« Reply #4 on: May 20, 2014, 08:58:48 AM »
I'd take a punt a whack a MTG-2 in it. You know you want to and you know I want to know.  :P
When the big picture is to big, look for a point you can start at and build from there.

Offline 18sixfifty

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Re: Fenix TK61
« Reply #5 on: May 20, 2014, 04:50:57 PM »
well if I could figure out how to put a copper "pill" in it then I would be.

Offline TomE

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Re: Fenix TK61
« Reply #6 on: May 20, 2014, 10:38:48 PM »
I modded two TK61's - resistor modded both. One did a de-dome. The hot spot though looks a mess on a white wall. I measured 480 kcd at 4.72A to the LED. What did you do to focus it? Looks like the factory LED centering piece is too small so it moves around, impossible to get the LED centered.

Offline TomE

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Re: Fenix TK61
« Reply #7 on: May 20, 2014, 10:41:41 PM »
Oh sorry - haven't been on this forum in a long time. My password didn't work and the forum didn't send me an email (checked junk folder). So created a new acct. Totally forgot bout this forum - nice and quiet so far - like it!

Offline 18sixfifty

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Re: Fenix TK61
« Reply #8 on: May 20, 2014, 11:03:19 PM »
Oh sorry - haven't been on this forum in a long time. My password didn't work and the forum didn't send me an email (checked junk folder). So created a new acct. Totally forgot bout this forum - nice and quiet so far - like it!


I shaved the centering ring down a little flatter and at the same time this left some of that chaffed up plastic so it gets a little better grip on the emitter. I think I must have screwed and unscrewed the head about 50 times while pushing down on the lens at the same time to get it centered the way I wanted. I was surprised that it didn't come centered right in the first place. On a light this expensive you would think that they would have managed to do that part right. Still it's a very cool light.

Offline Spasmod

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Re: Fenix TK61
« Reply #9 on: May 20, 2014, 11:07:14 PM »
Oh sorry - haven't been on this forum in a long time. My password didn't work and the forum didn't send me an email (checked junk folder). So created a new acct. Totally forgot bout this forum - nice and quiet so far - like it!

No worries Tom, I figured that's what had happened since we migrated over from flashlight emporium. I'll delete your old account as I had brought it over from the old one anyhow.

Cheers mate

Spas

Offline Spasmod

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Re: Fenix TK61
« Reply #10 on: May 20, 2014, 11:12:58 PM »

I shaved the centering ring down a little flatter and at the same time this left some of that chaffed up plastic so it gets a little better grip on the emitter. I think I must have screwed and unscrewed the head about 50 times while pushing down on the lens at the same time to get it centered the way I wanted. I was surprised that it didn't come centered right in the first place. On a light this expensive you would think that they would have managed to do that part right. Still it's a very cool light.

Do you have any pics Brad ? I'm hoping if I do get one of these it doesn't turn into a nightmare.. like you said, it shouldn't need to be done on a new light. I always though Fenix workmanship was top notch.

Offline TomE

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Re: Fenix TK61
« Reply #11 on: May 20, 2014, 11:43:48 PM »
It's sic how wide the reflector is - about 96mm ID I believe. Would love to see 6+A on this. Maybe best thing to do would be to re-wire the carrier to 4P, then use a FET driver with e-switch firmware in it. Actually I could add 2 e-switch support pretty easy, I think. Considering how it throws with so low stock amps and low stock lumens, it's not surprising you can get 600 kcd out of it on 5.75A to the LED.
For the centering piece, I sanded it down too - just on top, but it's definitely too small for the opening. Was thinking of measuring the opening and maybe trying other sizes I got here, but that cut-out in the bottom of the reflector is custom for the stock alignment piece.

Offline TomE

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Re: Fenix TK61
« Reply #12 on: May 20, 2014, 11:45:00 PM »
Did you ever see such thick wires in a stock light? I haven't. I believe they are 16 AWG. Wow...

Offline 18sixfifty

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Re: Fenix TK61
« Reply #13 on: May 21, 2014, 12:27:49 AM »
Yep very thick, thickest I have seen on any light. I have to think that the driver has got to be very efficient the way it's set up. How I didn't get into the driver to do the resistor mod yet. How did you get the driver out? Is it just glued in? I figured I could just tap on it from the top and tried a little bit but not with too much force. I'm not sure I will do the resistor mods yet anyway but I did want to look at it.

Offline TomE

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Re: Fenix TK61
« Reply #14 on: May 21, 2014, 01:21:15 AM »
Do you mean removal of the contact board? If so, was pretty easy - there may be some light glue there, but there are two spots where the side of the contact board is exposed -- its very thick, like the wires. I used a really flat tip screwdriver type of tool and pried it up. Think for one, might have used a regular screwdriver on the exposed edge and gave it a tap -- not sure.