# The "FETtie" - 500W Tailcap Switch for Z41 / FM26XXX



## VanIsleDSM (Oct 6, 2010)

Introducing the ultimate high power tailcap switch for Z41 and FM26XXX hosts.

Designed as a suppliment to the 1450 Lumen P60 Quad drop-in. This switch's capabilities extend well beyond it's originally intended necessity.

The P60 Quad thread is quite longwinded now, so I wanted to make a separate information thread for the FETtie for any questions or comments.

With any Linearly regulated or Direct Drive light, this will give you more current, and more lumens.

With any Buck, Boost, or Buck-Boost regulators, this will reclaim power currently being eaten by your higher resistance switch, and provide longer runtimes.














How does it work?

The FETtie uses a solid state semiconductor, a MOSFET. Essentially a relay, with no moving parts, which is turned on by the clicky switch. The Clicky switch itself only conducts 100 nanoamps, that's 0.0000001A, to activate the semiconductor. This means the clicking mechanism will last nearly forever, as the electrodes will not wear from arcing.

The FETtie uses a small coin battery, 1216 size. You do not need to worry about this battery becoming depleated however. It's like the battery in a watch, it will last for many years. Even being left on, the switch will draw less current from the coin cell than it's self discharge rate


Specifications:

Current - 25A+

Voltage - 12V MAX

0.0034 ohm Rds(on) MOSFET resistance

Beryllium copper spring, Pure silver plated for extra conductivity, 24K gold plated contact area.

Gold plated contacts from the FETtie to host.

Threaded brass body

Panasonic 1216 coin cell included



Here are some graphs comparing it's performance to a McClicky switch with various cells using my 4.2A Quad drop-in. These results would be compounded with higher currents.

















I'll update with some pictures soon. These are only available to those on the closed P60 Quad drop-in waiting list at the moment, but they will be available for all shortly.


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## Drywolf (Oct 6, 2010)

I have the host ready now I need the FETtie and drop in. Paypal ready...


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## Linger (Oct 6, 2010)

+1, charts look great.
I'd be in the waitlist for one tailcap switch but you said there' isn't a list. So I'll just wait  And say it sounds good. Please update with pics when able.


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## Justin Case (Oct 6, 2010)

What driver was used in the tests to produce those graphs?


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## Linger (Oct 6, 2010)

VanIsleDSM said:


> Designed as a suppliment to the 1450 Lumen P60 Quad drop-in. This switch's capabilities extend well beyond it's originally intended necessity.
> 
> Here are some graphs comparing it's performance to a McClicky switch with various cells *using my 4.2A Quad drop-in*. These results would be compounded with higher currents.


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## Justin Case (Oct 6, 2010)

Yes. That's the drop-in. What is the driver in the drop-in?


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## Hack On Wheels (Oct 7, 2010)

Justin Case said:


> Yes. That's the drop-in. What is the driver in the drop-in?



I'm going to venture a guess that it is a linear regulator based driver, with 12 chips to give the 4.2A. I can't do any better than a guess though.

This idea sounds great; I wonder what FET is being used in it? 500W capability is pretty serious business.


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## CKOD (Oct 7, 2010)

Hack On Wheels said:


> I'm going to venture a guess that it is a linear regulator based driver, with 12 chips to give the 4.2A. I can't do any better than a guess though.
> 
> This idea sounds great; I wonder what FET is being used in it? 500W capability is pretty serious business.


 

You think thats impressive, look at what the boys at STmicro have 
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=497-7614-1-ND

Thats an insanely small package (9mm x 14mm) for carrying triple digit currents, but looking at the charts, it needs at least 5v to to reach a nice low resistance, and 10v to get its .001 ohm spec. For single short (.1 mS) pulses they spec over 1000 A in the "safe operating area" think thats enough to instaflash some hotwires? 


Either way, not bagging on the FETtie, just pointing out that there are some pretty crazy semiconductors out there if you have the $$ for them (though $6 is surprisingly low for the above FET)


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## VanIsleDSM (Oct 7, 2010)

The FET above is over 1/2" x 1/2" fitting it into a circlular area. If You could fit that into a Z41 switch with 10V, or even 5V of battery then my hat is off! ..and I would like to borrow your shrink ray for some of my currently inconceivable projects.

Full current rating of the FET in the FETtie is 80A, I derate to 25A for safety sake.

Go nuts if you want, but pay attention to the heat in your tailcap. The FET is sinked through the brass threading into the tailcap, so if you're going for serious amperage, maybe put some thermal grease on the threads.

If anyone needs triple digit amperage, just ask me. I'm sure however, that the FETtie will cover most all needs. I'd be really interested to make a "super FETtie" if there was a need for one though.

It's a low drop-out linear driver with 4 separate outputs. One for each LED. It's for use with a single cell. Mode configurable, low battery warning, thermally protected.

The graphs stop at 1.84A, a figure corresponding to 750 lumens, or half brightness of the drop-in.


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## CKOD (Oct 7, 2010)

VanIsleDSM said:


> The FET above is 1/2" x 1/2" If You could fit that into a Z41 switch with 10V of battery then my hat is off! ..and I would like to borrow your shrink ray for some of my currently inconceivable projects.
> 
> Full current rating of the FET in the FETtie is 80A,* I derate* to 25A for safety sake.


I figured it was derated, as bad things tend to happen when you run transistors at their nameplate current and voltage ratings without consideration. I'll save the 280A beast above for if I ever make a 2kW + light (20x CSM-360 showerhead? yes please  )

Impressive results in the increase in regulated run time in your graphs, any idea how much of a resistance drop it is vs the McClicky?


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## LightJunk (Oct 9, 2010)

How much will it be? I may want one.

Thanks.


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## donn_ (Oct 9, 2010)

I can vouch for how well this switch works with the 4x XP-G drop-in, which measures 5.6A at the tail on a 26650 cell. It's a pleasure to use.

Here's the host:






A ribbed M2 bezel on an FM 1x26650 tube/tail with the FETtie in the tail. It took some time to get used to the reverse clicky, and I still miss momentary, but once accustomed, I was right at home with it.

I tried the same bezel/drop-in on a BigLeef setup, which has a 10A rated tailcap (Judco, IIRC), and the difference in brightness was notable. The FETtie is much brighter.

I plan to test the switch with some incan hotwires soon.


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## FroggyTaco (Oct 9, 2010)

Any chance of making a forward clickie version someday?


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## flashfiend (Oct 9, 2010)

As a nighttime jogging light when I need to change brightness with the light still on I think I am going to appreciate it being a reverse clicky. I think forward clickies are more for those times when you want momentary so you don't give up your position in certain situations. I've still got my McClicky for those. Now I just have to receive my FETties so I can make the comparison myself.


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## VanIsleDSM (Oct 9, 2010)

They do each have their advantages, and people have different preferences for different applications.

I would like to offer a forward clicky version, and I'll be looking into it.


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## FroggyTaco (Oct 9, 2010)

VanIsleDSM said:


> They do each have their advantages, and people have different preferences for different applications.
> 
> I would like to offer a forward clicky version, and I'll be looking into it.



Very cool..I want to have a 7-9 neutral XP-G light in a cut down Mag C with a tail switch driven by 2-26500 IMR's & a McClicky will be the weak link in the config due to current draw if my calcs are correct.


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## ptolemy (Oct 10, 2010)

Donn_ got it back, how exciting.

I am awaiting mine lovecpf


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## donn_ (Oct 10, 2010)

The new threaded one hasn't arrived yet.


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## donn_ (Oct 12, 2010)

New ones arrived today. _*BIG*_ improvement with the threaded one for the FM host.

:thanks:


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## flashfiend (Oct 12, 2010)

Pics?


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## donn_ (Oct 12, 2010)

Your wish is my command!:nana:












Installed in Z41 and in FM 26650 host:


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## flashfiend (Oct 12, 2010)

Thanks donn_, you and the FETtie are awesome. Btw, is that brass collar fixed to the switch or do the two parts slide freely between each other? Hopefully I will find out for myself very soon.


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## VanIsleDSM (Oct 12, 2010)

Just as I added pictures of my own!

The clicking mechanism itself is friction fit into the white plastic collar. You remove the switch to replace the battery, or the switching mechanism if need ever be.


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## donn_ (Oct 12, 2010)

Good news! The switch screws easily into an SW01, and works perfectly. :twothumbs


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## flashfiend (Oct 12, 2010)

Just got my FETties today. Very robustly built. Be great for a single level direct drive sst-50 or hotwire. I did have a difficult time twisting it into a z41 but did manage to get it in.


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## donn_ (Oct 13, 2010)

For the first time, I wish I had a sphere.

I just did a comparison of a Moddoo 3x XP-E, 700 lumen drop-in, in an FM 1xC (AW) host and in a bored 6P with the Z41-mounted FETtie. There is no question it is brighter on the FETtie...I'm guesstimating at least 10-15% brighter.


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## flashfiend (Oct 13, 2010)

I don't know about brighter, but I really like multi-mode lights with the reverse clicky. And the FETtie's robust build with higher current draw lights is a big plus for me. And though I can't definitively say if the FETtie is brighter than either the McClicky or Zero-Rez switch, I can tell you it is at least as bright.

If I didn't have a semi-difficult time twisting it into my tailcap, I'd say this is clearly the #1 switch made for SF-compatible lights. For now it is #1 with room for improvement.


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## VanIsleDSM (Oct 13, 2010)

What exactly was difficult, getting the threads to start? Are you sure your tailcap has no thread damage? 

All of the threads are cut on the same bar, and then parted into pieces, I also test fit every single switch or drop-in I make. If one is having trouble, then they all should be, which isn't the case. Leads me to believe it may be your tailcap.


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## donn_ (Oct 13, 2010)

I've had them in an FM cap, an SW01 and 2 different Z41s, and there's been no problem.


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## flashfiend (Oct 13, 2010)

I've tried with 3 different tails and they were tight going in. One of the tails was NIB. It was just difficult for me to get them in. No thread damage present. I've had success with McClicky kits and AW soft start.

***Just tried it again. It went in easier but it was still a tight fit.


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## LV426 (Oct 15, 2010)

I must say, this is super cool!!!


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## ptolemy (Oct 18, 2010)

VanIsleDSM said:


> What exactly was difficult, getting the threads to start? Are you sure your tailcap has no thread damage?
> 
> All of the threads are cut on the same bar, and then parted into pieces, I also test fit every single switch or drop-in I make. If one is having trouble, then they all should be, which isn't the case. Leads me to believe it may be your tailcap.


 Van, have you had a chancer to mail my bezel/tailcap back>?

I am giddy with anticipation!


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## Mettee (Oct 19, 2010)

I would like to try one of these!


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## powerup93 (Oct 29, 2010)

Hi VanIsleDSM,

I hope others can chime in as well, but I was wondering what the switch press feel is like. Is it a hard press or soft press? Being a reverse clicky based unit, does it feel like a stock solarforce l2 switches?


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## flashfiend (Oct 30, 2010)

The switch pressure is about the same as the McClicky. I have no experience with the Solarforce switches. Oveready hardpress rubber boots should be able to work with this switch to increase switch pressure.


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## VanIsleDSM (Nov 1, 2010)

I'm not sure what a solarforce switch feels like either, but it is about the same as a McClicky as flashfiend has mentioned.

With an FM host the rubber section is left in the boot. With a Z41 the stock boot must be replaced with a supplied boot that has the rubber section cut out of the middle.

I have ammended the original post. I have started using a different MOSFET that has a lower resistance, 0.0034 instead of 0.0046. It also has a package limited current of 40A, making it safer. The only drawback is the voltage maximum is 12V instead of 20V, but I do not think this will affect many people.

In anyone requires a FETtie for a situation calling for more than 12V, let me know, and I can built one with the 20V MOSFET.


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## richpalm (Mar 20, 2011)

Price? Availability?

Rich


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## mknewman (Mar 20, 2011)

I have a couple of the original run of the FM26650 bodies and the FETtie doesn't work properly in it. I tried snugging it down, but it never really seats all the way in the way a AW Softstart does. It would not make contact at all with the tail (annodization on the threads) until I added a M10 washer but it now works perfectly, although it still sticks up about 1mm above the 'shoulder' of the tailcap threads. Hope this helps out others, it took me a while to figure out what was going on. BTW, I think you might be able to use lye CAREFULLY with a QTIP to remove the annodization but I found this an easier fix.

Marc


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## seahunt (Mar 21, 2011)

Where can these nifty switches be purchased??
Regards, Chuck


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## stoli67 (Mar 21, 2011)

I love the FETie that I have and would like two more.... esp one for the Septa when it becomes available....

I like it function better than the McClicky

I even bought 2 old style FM tail caps for my new FM26650 hosts so that the switches will slip straight in...... 

Jesse... I will take two of these whenever they are available.


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## tuelleric (Mar 26, 2011)

VanIsleDSM said:


> I would like to offer a forward clicky version, and I'll be looking into it.



Any news on that by the way?


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## richpalm (Mar 26, 2011)

seahunt said:


> Where can these nifty switches be purchased??
> Regards, Chuck



Seems no one wants to answer this...


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## tstartrekdude (Mar 27, 2011)

Nowhere yet with out buying a flood monster from VanIsleDSM...not tell we bug him enough to make some foe the rest of us anyhow.


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## powerup93 (Mar 28, 2011)

I got a FETtie and I had a question hopefully VanIsleDSM or users could report on.

Figuring that the current was passing through the FET instead of metal pieces that lie in click switches, I had imagined that there wouldn't be a "switch whine" like when using other clicky switches. I have a quad L,M,H and on medium I can hear the whine as I put the tail up to my ear. On low and high, I would say that I cannot hear any whine.

I thought that the whine essentially came about because of resistance in the springs/switches of clickies; am I wrong about that?


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## onetrickpony (Mar 28, 2011)

I always thought the whine came from chips cycling at very high frequencies, basically a switch opening and closing at audible levels of Hz to the human ear. I've never had a tail cap whine, I only hear it where the driver is located.


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## VanIsleDSM (Mar 29, 2011)

You're right, the whine is due to resistance.

It's from the FETtie not making proper contact in your host, not the switch itself. There's either some debris in there or you may just need to snug it down slightly more. Here's a quote from another member.

"On low it has minimal inductor(?) whine, on medium it whines as loud as my old HDS U60XRGT, pretty loud in a quiet room. In normal use with other noises, it most likely wont be noticeable. I can easily hear it on medium with the TV on and my arm strtched out. On high it is silent, no whine. <<<EDIT: Jesse was right, my FetTie wasnt tightened, quick fix, no whine"

There is no sales thread for FETties on their own right now. I am planning to have one eventually, but I do have higher priorities at the moment, like getting the multi-mode Septa going. I will try to put up 10 or 15 for sale on their own within the next couple weeks though for those who have been waiting for just the switch.


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## ShineOnYouCrazyDiamond (Apr 26, 2011)

Please add me to your wish list for purchasing a FETtie with a reverse clicky when available as a separate item.


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## carl (May 4, 2011)

"Too Good to be True" request: Please make one to fit the Maelstrom S12, forward clicky.


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## Norcimbus (Jun 29, 2011)

Please include me on the FETtie wishlist. I would like to buy 2 when available.


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## mash.m (Jul 1, 2011)

i am also in when you put some into the sell.

thanks, markus


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## flex76italy (Jul 1, 2011)

Me too in list for the FETtie switch only.

Thanks


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## simplec6 (Jul 5, 2011)

I would like to be added to the list as well for 2


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## Obijuan Kenobe (Jul 12, 2011)

I am trying to read the thread to find out for myself, but was unable. Sorry.

Is this switch readily swapped with any McClicky? I guess I am wondering if I can put these in a 123 host I have (with a McClicky) by just unscrewing one and inserting the new?

If so, I am interesting in having one if they become available separately.

obi


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## badtziscool (Jul 14, 2011)

VanIsleDSM said:


> They do each have their advantages, and people have different preferences for different applications.
> 
> I would like to offer a forward clicky version, and I'll be looking into it.


 
Hello.

Any news on either a forward clicky version or a sales thread for individual FETtie?


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## mcmc (Aug 4, 2011)

This whole time since I first heard about this cool switch, I thought it would be forward just like the stock switch. Now I realize I can't use it in my mod build because it requires a forward. Just a suggestion: may want to put that it's a reverse clicky in the original post?


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## simplec6 (Aug 4, 2011)

Available shortly post in oct. '10? It's Aug. '11.


That is one helluva shortly.


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## VanIsleDSM (Oct 24, 2011)

Sorry for the long wait. They have been available for a long time along with one of my 1900 Lumen P60 Quad S2 drop-ins, I didn't have the equipment to be able to build enough to supply any more than that.

Not any longer however... 

*FETties are ready**!

*I don't have the sales thread up yet, I'll be writing it up and posting it tomorrow, I want to take some new pictures. Buy as many as you like now with no restrictions.

Just PM me for now, thread will be up soon.


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## VanIsleDSM (Oct 26, 2011)

Sales thread now up:

http://www.candlepowerforums.com/vb...e-for-Z41-and-variants.&p=3779589#post3779589

The new FETties are better than ever, no major changes but definitely more refined.


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