# Show your 12P/12ZM/12PM(T3,SRTH,or mod, NOT M4) !!



## cenz (Sep 22, 2008)

i'm user too, I very love my 12pm sofar, but the stock bulb is quite un-practical...

anyway, it is classic and powerful flashlight ever~

and... would you like to describe your moding info?







my 12PM and 9P moding


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## willrx (Oct 1, 2008)

I recently purchased a 12ZM and would like to know more about it. It is currently en route. I'll post some pics when it arrives.


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## Size15's (Oct 1, 2008)

I still get a buzz from using my 12PM with T-Series TurboHead and N62. On fresh batteries for a few minutes it's just a wonderful beam.

I've always wished I purchased the 12ZM instead back when I had the chance.


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## willrx (Oct 1, 2008)

Wow, what an honor. Thanks for replying to this thread. Do you have time to share any information on the 12ZM or its history? Thanks.


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## Size15's (Oct 1, 2008)

It's a *Flash*light in the real sense of the word. If you need constant-on light output select an M6.

The 12ZM was created to provide specialist law enforcement and military operators with a "Tactical Entry Light" - to overwhelm those inside with a massive slam of brilliant white light. Since it would only be used for a few seconds, perhaps up to a minute at time it was decide to suck every last possible drop out of the four batteries for maximum light output.
At the time the 12ZM/12PM were released they represented a truly awesome light output for what is actually a light-weight, compact and easily manipulated flashlight [compared to the likes of the Streamlight SL-35X which was perhaps the only other flashlight capable of similar output]

The N62 does not take any prisoners or suffer pretenders when it comes to feeding it. Use only Duracell DL123A or SureFire SF123A batteries.
They must all be new and fresh and you'll get two 3-minute constant-on bursts of high quality light output, although the second burst once the batteries have cooled down lacks the extended brilliance.

When used too much (for example constant-on) the batteries overheat and go into "thermal shutdown" to prevent themselves from exploding. Swap out to a fresh set and allow the hot ones to call down for 10 minutes or so.

It's not a flashlight for those who care about the cost of feeding it plenty of DL123A or SF123A batteries.

Al


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## willrx (Oct 1, 2008)

Al,
Thank you Sir! It would have taken years to learn what you've shared here. Really appreciate the lesson.:thumbsup:
Will


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## MorpheusT1 (Oct 1, 2008)

I have one Minty Fresh comming my way aswell.
:naughty:

What kind of bulb options do i have and what runtimes to expect from the diffrent types?
My plan was just to pop a Tower module and a Seoul driven at 1300mA.
Not the Brightest setup though..


Benny


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## cenz (Oct 2, 2008)

I just only hv 12PM, N62 is really a "luxury battery terminator", as for "thermal shutdown", it 's never happen sofar, may be my CR123a quality is not excellent (low current)...

Recently, I've upgraded my 12PM into 18650 field, 2x Panasonic Japan 2350mah li-ion, it is rated 3.5A~(4.2V) and ~3.3A(3.8V).


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## AW (Oct 2, 2008)

I still play with my 12ZM once in awhile. Can't think of anything that can replace it.


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## MorpheusT1 (Oct 2, 2008)

Hi AW,

Do you run the regular bulb in it?

Any Recommendations Bulb Wise?


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## AW (Oct 2, 2008)

Benny,

I am running the N62 and sometimes MN60 / MN61.

AW


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## MorpheusT1 (Oct 2, 2008)

Cool,

Seems the N62 is hard to find Or is it?
I found this HO-M4A alternative from Lumensfactory.

Cant wait to get mine.


Regards,
Benny


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## cenz (Oct 2, 2008)

AW said:


> Benny,
> 
> I am running the N62 and sometimes MN60 / MN61.
> 
> AW



Hi AW,

How about the beamquality when using MN60/61 with SRTH? any beam-hole?

Size15's is correct, who said N62 is not perfectly performance with SRTH. 3"Turbohead is more perfect with N62, very tight [email protected]@


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## cenz (Oct 2, 2008)

MorpheusT1 said:


> Cool,
> 
> Seems the N62 is hard to find Or is it?
> I found this HO-M4A alternative from Lumensfactory.
> ...



So surprising, N62 is still available in Surefire Taiwan
http://www.surefire.com.tw/lamp_assembly.html

I tried 12PM(SRTH)+HO-M3T is very good beam, it similar to N2~


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## AW (Oct 2, 2008)

Cenz,

MN60/61 w/ SRTH has no donut hole. Using the EO-M3T in the 12ZM has a tighter beam and throws further than in a M6.

AW


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## Size15's (Oct 2, 2008)

The original TurboHead for the 12PM/12ZM was the dedicated, T-62 TurboHead or TRTH (Threaded Rim TurboHead). It was only supplied with the SRTH (Short Rim TurboHead) once the TRTH were used up.
The reflector finish is quite different making for different beams.


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## cenz (Oct 2, 2008)

Size15's said:


> The original TurboHead for the 12PM/12ZM was the dedicated, T-62 TurboHead or TRTH (Threaded Rim TurboHead). It was only supplied with the SRTH (Short Rim TurboHead) once the TRTH were used up.
> The reflector finish is quite different making for different beams.



So.. Is SRTH a rare & momentary version TH, rather than T62?


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## Size15's (Oct 2, 2008)

cenz said:


> So.. Is SRTH a rare & momentary version TH, rather than T62?


The T-62 (in this instance I understand there is a "-" dash) was the original compact (2.5" diameter) TurboHead [compared to the 3" diameter T-Series 'Extended Range' TurboHeads]

SureFire made the T-62 (TRTH = Threaded Rim TurboHead) to accept a screw-in IR BeamFilter that was only available for a short time to very select group of clients.

Without the wider need for the threading SureFire created the SRTH (Short-Rim TurboHead). Although it was supplied as part of some later 12PM/12ZM/LeopardLights, as an accessory the SRTH was exclusively available through a SureFire Dealer Lagger Pro (LPS) and several batches were made.

It was determined that the 3" diameter reflector did not afford a significant enough difference to justify the big difference in bulk so SureFire developed their T-Series replacement (the KT TurboHead) at 2.5" diameter, and their Millennium [Series Shock Isolated] TurboHead around the 2.5" diameter form-factor (12PM = M4).

Al


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## willrx (Oct 3, 2008)

Received my sealed NIB 12ZM. My tail cap, as viewed through the plastic bag, is slightly different from AW's pictured above. Mine does not have a "12ZM" designation. Later version perhaps? Might need Size 15's on this one. Pictures coming soon.


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## Size15's (Oct 3, 2008)

does sound like one from a later batch...


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## loszabo (Oct 3, 2008)

I want one!!! :thinking:


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## cenz (Oct 3, 2008)

willrx said:


> Received my sealed NIB 12ZM. My tail cap, as viewed through the plastic bag, is slightly different from AW's pictured above. Mine does not have a "12ZM" designation. Later version perhaps? Might need Size 15's on this one. Pictures coming soon.




[email protected]@@


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## willrx (Oct 3, 2008)

Huh?


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## cenz (Oct 3, 2008)

willrx said:


> Huh?



Sorry , my english is not good;

I mean that waiting for your new 12zm pic.


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## willrx (Oct 4, 2008)

That's all for now. Haven't opened it yet.
Will


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## cenz (Oct 4, 2008)

willrx said:


> That's all for now. Haven't opened it yet.
> Will



wow, Is the SF leaflet included inside the box?

thanks your sharing~


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## loszabo (Oct 4, 2008)

So, this is the grand-daddy of the M4, right?


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## willrx (Oct 4, 2008)

Yes, the owners manual was included in the box.


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## willrx (Oct 4, 2008)

loszabo said:


> So, this is the grand-daddy of the M4, right?



As I understand, yes. This one comes with the 500 lumen N62 lamp though. A real battery destroyer.


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## cenz (Oct 4, 2008)

willrx said:


> As I understand, yes. This one comes with the 500 lumen N62 lamp though. A real battery destroyer.




Do you have M6 or M4 ? I'm wondering how are the beamshot comparisons of Mx(KT4) vs SRTH~


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## willrx (Oct 4, 2008)

I have an M6 on the way. Surely others will chime in with thoughts on the comparison between the two. There may not be much difference.


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## Size15's (Oct 4, 2008)

That is a later batch with the SRTH so it's beam is slightly different to the T-62.
The "KT4" TurboHead Kit No.4 uses the Millennium TurboHead. To refer to the Millennium TurboHead as the "KT4" is wrong. I dislike it more than "HAII"

The Millennium TurboHead and KT TurboHead have the same, more disruptive stochastic reflector finish compared to the less forgiving SRTH and T-62 reflector finishes. The N62's filament is not as large nor as 'in need' of a more dispersing finish so to my eyes the N62 beam looks practically identical in the Millennium TurboHead / KT TurboHead, and the SRTH, and the T-62.
The MN60 and MN61 on the other hand don't always produce perfect beams in the older TurboHeads.


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## cenz (Oct 5, 2008)

Size15's said:


> That is a later batch with the SRTH so it's beam is slightly different to the T-62.
> The "KT4" TurboHead Kit No.4 uses the Millennium TurboHead. To refer to the Millennium TurboHead as the "KT4" is wrong. I dislike it more than "HAII"



What did you mean the "HAII"? is it T series?


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## Size15's (Oct 5, 2008)

cenz said:


> What did you mean the "HAII"? is it T series?


"HAII" is a term people ignorantly use to refer to type II anodising.
"HA" stands for 'Hard Anodised' and is the name for type III anodising to differentiate it from the less durable type II anodising.
Both these types come from the US Military Specification MIL-A-8625.

So the term "HAII" is like saying "Hard Anodised not Hard Anodised"


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## willrx (Oct 5, 2008)

Size15's,
I'd like to say thanks for adding such wonderful content to this thread. This is sure to help many folks in the future. Prior to this there were only a couple of short threads on the 12PM/ZM.:thumbsup:
Will


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## Size15's (Oct 5, 2008)

Thanks - it's not often any longer we get to talk about the original lights that began all this...


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## sween1911 (Oct 7, 2008)

Whoa, how was I not keeping up on this? Factory sealed 12ZM? I think I'm going to cry!

Seriously, that's a nice find!


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## sween1911 (Oct 7, 2008)

(deleted)


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## cenz (Oct 7, 2008)

Size15's said:


> "HAII" is a term people ignorantly use to refer to type II anodising.
> "HA" stands for 'Hard Anodised' and is the name for type III anodising to differentiate it from the less durable type II anodising.
> Both these types come from the US Military Specification MIL-A-8625.
> 
> So the term "HAII" is like saying "Hard Anodised not Hard Anodised"



Thanks your expert-graded infomation first, and hope you can have 12ZM .

Recently, I'm thinking and considering to replace the SRTH plastic lens to glasses, but it seems very risk...


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## Size15's (Oct 8, 2008)

cenz said:


> Thanks your expert-graded infomation first, and hope you can have 12ZM .
> 
> Recently, I'm thinking and considering to replace the SRTH plastic lens to glasses, but it seems very risk...


Thanks - I'm not in the market for a 12ZM - that ship has flown the coop.

I'm not sure it will be possible to replace the Lexan window for a glass window. The Lexan window is secured by a push-in snap-fit method that requires the polycarbonate flexibility.


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## MorpheusT1 (Oct 9, 2008)

Got mine in today 















No box or manuals with this one im afraid,
The O-Rings was dry as hell and the Gubber grip was hardened.
Lubed it up including the Rubber grips after i had slided them off same with the rubber switch cover.

Now,as new.
No dings no nothing. Perfect specimen.

I put some fresh SF 123`s in it and fired it up,and the beam is insane.
Cant wait to compare it to my M6.





I`ll keep it in my shelve and use the M6 for the real stuff.


Benny


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## cenz (Oct 9, 2008)

MorpheusT1 said:


> Got mine in today
> 
> No box or manuals with this one im afraid,
> The O-Rings was dry as hell and the Gubber grip was hardened.
> ...



"12Z"!!! I have never seen that model sofar.. to Size15's : would you explain that version ?

Benny, 

I think your turbohead is the original version that specially for N62 --- T62, and the beam must be tighter than KT4 w/ MN21, um.. I 'm also imagining how the beam from T62 head +MN21 is...

thanks your sharing


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## Size15's (Oct 9, 2008)

cenz said:


> "12Z"!!! I have never seen that model sofar.. to Size15's : would you explain that version ?


There are two versions - the straight-bodied "P" and CombatGrip bodied "Z".
I'm not quite sure why SureFire added the "M" with the 12ZM and 12PM.
(there is no difference other than the etching AFAIK)
3P, 6P, 9P, 12PM
6Z, 7Z, 9Z, 12ZM
There are plenty of odd models not quite fitting the general 'rules' so I've always chalked the "M" up as one of the many ineffable things about SureFire.




cenz said:


> Benny,
> I think your turbohead is the original version that specially for N62 --- T62, and the beam must be tighter than KT4 w/ MN21, um.. I 'm also imagining how the beam from T62 head +MN21 is...


That's right - it is the T-62 (note there is a "-" in T-62) - the so-called Threaded-Rim TurboHead (note the capitalisation of TurboHead)
Note the "KT4" is not a TurboHead - it is a TurboHead *Kit* featuring the _Millennium TurboHead_. The so-called "KT TurboHead" is the one supplied with the KT1, KT2 & KT5 TurboHead Kits. (The KT3 being special all by itself just like the T3 is unique to itself)

I've powered the MN21 in the T-62 and the beam is disappointing with several of the MN21 Lamp Assemblies I have. Not enough stochastic disruption on the reflector to clean-up the beam I guess. Also it gets very hot and I don't want to risk damaging the Lexan window.
The N62's runtime is so short that the risk of window damage in use is minimal - I've put in the region of 50 or so sets of batteries (mostly Duracell DL123A) through my 12PM with no sign of heat damage to the window.

Due to the power of the N62 I urge people to replace their stock 12PM/12ZM TurboHeads with Z41-BK LockOut TailCaps. This way the flashlight can be disabled to prevent accidental activation and not to mention wasting the batteries. Accidental activation in a confined space could very well result in the flashlight starting a fire, or perhaps even the batteries going critical.

Al


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## cenz (Oct 9, 2008)

Size15's said:


> There are two versions - the straight-bodied "P" and CombatGrip bodied "Z".
> I'm not quite sure why SureFire added the "M" with the 12ZM and 12PM.
> (there is no difference other than the etching AFAIK)
> 3P, 6P, 9P, 12PM
> ...



um.. I found a website where describe 12zm that called - 12ZM Magnum-Light; as i know, the first generation of M6 that was also called M6 Magnum light... is that right?

http://www.ge-ha-tec.com/neu/surefire/surefire08.htm


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## MorpheusT1 (Oct 9, 2008)

Very cool,

Thanks for the info s15`s.


I did not even notice the threads inside the bezel of the head until you pointed it out.
:laughing:


Gotta hit the sack,
Benny


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## Size15's (Oct 10, 2008)

cenz said:


> um.. I found a website where describe 12zm that called - 12ZM Magnum-Light; as i know, the first generation of M6 that was also called M6 Magnum light... is that right?
> 
> http://www.ge-ha-tec.com/neu/surefire/surefire08.htm


That's a good enough explanation for the M as I think we're likely to get.
I love that website referring to it as a "_Lichthammer!_" - Light Hammer!


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## maxspeeds (Dec 12, 2008)

bump for any possible beamshots of these lovely lights


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## cenz (Dec 14, 2008)

maxspeeds said:


> bump for any possible beamshots of these lovely lights



Hi,

here is a beamshot from Brock's website which included 12PM(SRTH):


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## Size15's (Dec 14, 2008)

Perhaps you could send Brock a pm to ask whether you can hotlink one of his images?


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## cenz (Dec 14, 2008)

Size15's said:


> Perhaps you could send Brock a pm to ask whether you can hotlink one of his images?



Hi,

Sorry that the image which I just posted without his approval; I just PM him for that.


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## kelmo (Mar 7, 2010)

I just picked up a 12ZM. Just enough wear so as I won't baby it. It is a splendid light. The N62 lamp is a monster. Too bright for my tastes. I installed an MN60 LA and used it this weekend at a cabin I was staying in in the Sierra Nevada mountains. What really surprises me is how light weight it is. I'm glad I held out and didn't get an M4. This is an instant favorite!


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## Size15's (Mar 7, 2010)

Which TurboHead does your 12ZM have? 
Does it have the threaded rim?

How is the beam from your MN60 lamp?
In my limited experience the early TurboHead reflectors don't always flatter the modern lamps (the finish is too fine / the filament is too long)


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## kelmo (Mar 7, 2010)

Hello Size15s,

It is one of these;

http://www.cpfmarketplace.com/mp/showthread.php?t=216640

I believe it has the snap in lexan lens. No threads or retainer ring are present. This light came with a LOTC that is labeled with both Surefire and Laser products. The MN60 LA beam is round, and has a slight ghost of the filament image, dimmer than the balance of the hotspot when white wall hunting. The outer corona of the hotspot is a noticeably dimmer band. You really can't tell this when in use. The beam has a wide soft spill. It throws very well out in the field. Within 50m everything in front of you is illuminated extremely well. Lots of useful flood with a robust hotspot.

I compared the 2 lamp assemblies. They are the same length but the glass envelope on the N62 is only half the size of the MN60s I have.


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## Size15's (Mar 7, 2010)

That's the so-called "SRTH" or Short-Rimmed TurboHead.
Both that and the original "TRTH" have push-in, snap-fit Lexan windows.
The Threaded Rim was created for a never-released IR BeamFilter.

Thanks for the info on the MN60 beam in the SRTH - I assume the beam is much cleaner when you use the N62?
I think you're describing the less than perfect beam I can get when I put the MN60 or MN61 lamps in the TRTH, SRTH or T-Series TurboHeads.

FYI, that sales thread stated that the N62 Lamp Assembly has a runtime of 30 minutes. This is not even close to correct. More like 10 minutes.

I've put well over 60 sets of batteries through the N62 and it'll product excellent light for the first 2-3 minutes (until thermal shutdown), and then great light for the next 2-3 minutes and then depending on the batteries it will illuminate for one or two further 'sessions'.


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## lemlux (Jan 15, 2012)

Over the years I've acquired 2 @ T-3 heads, a T-62 TRTH, and an SRTH. Consistent with S15's observations, I've been unhappy with beam quality with MN60 and MN61 beam quality in these heads and burned out my last N62 several years ago.

Even so, I've had fun with a T-3 head loaded with an MN61 mounted on a bored-out D3 body with a pair of bored out longer extension tubes loaded with [email protected] 18650's. I take care to use weaker 18650 cells with significant voltage sag so as not to excessively shorten the service life of the MN61 with extreme overvolting. 

I've been watching the market for custom LED towers to allow longer extended run times with good beams that don't threaten to distort or melt the lexan lenses. For a year or so I've happily used a Nailbender tower with an XPG R5 with a 4V to 14V driver fixed at 1.4Amp rated at 320 lumens. I run this LED tower in my bored-out 12PM body with a pair of 18650's.

I'm about to buy his new (announced in December, 2011) 3-level 2.8Amp XML tower with a 3.4V - 9V driver for use with a pair of serial 18650's.


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## Size15's (Jan 15, 2012)

lemlux,
You know that the T3 TurboHead Kit is only for the 9N right? 
I think you mean "T-Series" (or perhaps T-type if you must).

You're right that "T-62" TurboHead Kit is one of a few rare SureFire model numbers to actually feature a "-" dash between the letter and the number.


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## lemlux (Jan 15, 2012)

Size 15's:

Most of what I've learned over the years about these turboheads has come from your gracious and voluminous posting. Years ago you explained the history of the threading on the T-62 TRTH, although I don't recall seeing the model designation at the time. 

One of the 3" units came to me on a used 12PM and the other one was a stand alone used unit that I discovered at a police equipment store. Both are identical. 

I accept your T-Series designation, and I don't think I encountered the T-3 designation before reading this thread.

Thanks for yet another clarification.


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## Kestrel (Jan 15, 2012)

Thanks kelmo for the bump - I missed this thread the first time around. Good stuff!


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## LE6920 (Jan 16, 2012)

Very interesting thread.

Do the 12ZM SRTH and the smaller (2 1/2"?) 12ZM tyrbohead take the same bulbs? I have seen a couple of these smaller turboheads on different lights(they look like 2 or 2 1/2") and often wondered on the bulbs they run off. I am guessing it is for a different shapped beam? Could you essentially have a 12ZM with a 9Z and a A19 adapter?


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## Size15's (Jan 16, 2012)

I have a detailed post on this somewhere with photos and whatnot.

Simply put, the 12ZM uses the N62 Lamp Assembly, and it uses a TurboHead that can accept other TurboHead Lamp Assemblies.
For example you could run the M4's MN60 and MN61.


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## Justin Case (Jan 16, 2012)

lemlux said:


> I've been watching the market for custom LED towers to allow longer extended run times with good beams that don't threaten to distort or melt the lexan lenses. For a year or so I've happily used a Nailbender tower with an XPG R5 with a 4V to 14V driver fixed at 1.4Amp rated at 320 lumens. I run this LED tower in my bored-out 12PM body with a pair of 18650's.
> 
> I'm about to buy his new (announced in December, 2011) 3-level 2.8Amp XML tower with a 3.4V - 9V driver for use with a pair of serial 18650's.



You might also check the new Malkoff MD60 tower.


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## Size15's (Jan 16, 2012)

LE6920 said:


> Very interesting thread.
> 
> Do the 12ZM SRTH and the smaller (2 1/2"?) 12ZM tyrbohead take the same bulbs? I have seen a couple of these smaller turboheads on different lights(they look like 2 or 2 1/2") and often wondered on the bulbs they run off. I am guessing it is for a different shapped beam? Could you essentially have a 12ZM with a 9Z and a A19 adapter?



The 12ZM and 12PM were supplied with either the TRTH (Threaded Rim) or SRTH (Short Rim) TurboHeads. Both are 2.5" diameter.
The "KT" and Millennium TurboHeads are also 2.5" diameter.
SureFire's T-Series Extended Range TurboHead was 3" diameter.

All these accept either the N-type (N1/N2/N4/N5/N62) or MN-type (MN15/MN16/MN20/MN21/MN60/MN61) TurboHead Lamp Assemblies.

The 12ZM features a CombatLight body for four-SF123A batteries.
It is possible to build a four-SF123A body using a three-SF123A + A19 adapter but if you use a "9V CombatLight" body such as the 9Z or Z3 with an A19 you'll find it difficult to reach the CombatGrip unless you have monster hands.


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## lemlux (Jan 17, 2012)

Justin Case said:


> You might also check the new Malkoff MD60 tower.



Thanks for the heads-up. Every time I consider a Malkoff assembly they are out of stock (as they are with this assembly). The brass tower is appealing but the 6.5V to 14V driver seems targeted at 3S and 4S primary and 3S Li-Ion power sources. The Nailbender 3.4V-9V driver seems better suited to the 2S 18650 application I am equipped for.


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## Justin Case (Jan 17, 2012)

lemlux said:


> Thanks for the heads-up. Every time I consider a Malkoff assembly they are out of stock (as they are with this assembly). The brass tower is appealing but the 6.5V to 14V driver seems targeted at 3S and 4S primary and 3S Li-Ion power sources. The Nailbender 3.4V-9V driver seems better suited to the 2S 18650 application I am equipped for.



I'm not sure I follow why the MD60's 6.5V lower limit means that the Nailbender tower is better suited to 2S 18650. By the time each 18650 cell is at 3.2V, it is essentially completely depleted. In fact, a 3.4V lower limit IMO means that you have a greater chance of overdischarging your cells.


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## lemlux (Jan 18, 2012)

Justin Case said:


> I'm not sure I follow why the MD60's 6.5V lower limit means that the Nailbender tower is better suited to 2S 18650. By the time each 18650 cell is at 3.2V, it is essentially completely depleted. In fact, a 3.4V lower limit IMO means that you have a greater chance of overdischarging your cells.



Some of my salvaged computer pack 18650's have reasonable capacity but suffer from high levels of voltage sag under high drain. A pair of these cells can sag to 3.2V when providing 2.8A to a LED without necessarily being "essentially completely depleted". These same cells are, as you observe, essentially depleted when I capacity check them on my old MH C777PLUS charger that can only discharge test at 0.33 A.


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## Justin Case (Jan 18, 2012)

Well, your first claim was that the MD60 wasn't as suitable for 2S 18650 vs the Nailbender tower. Now you've clarified that your 18650s are not really suited to deliver slightly more than 1C.

So I still don't understand your claim that the nailbender product is the better choice. The Malkoff link for the MD60 says that the tower draws 0.8A at 9V. Thus at 7.4V, you might draw about 1A. At 6.5V, about 1.1A. So I'm not sure where you get your 2.8A current draw figure for the MD60.

If the nailbender tower has the same driver efficiency and drive current as the Malkoff tower, then they are going to have the same battery current draw. So I don't see any issue regarding current draw and battery sag.

The Malkoff MD60 is advertised to deliver 450 OTF lumens. If we assume 40% lumens loss, that means 750 emitter lumens. For a T6 bin XM-L, that suggests about 2.4A drive current. The datasheet says the Vf is about 3.25V. If the driver is 85% efficient, then

0.85*7.4V*Ibatt = 2.4A*3.25V = 7.8W

Solving for Ibatt gives about 1.2A at Vbatt=7.4A. That's a bit higher than the value estimated above based on Malkoff's figure of 0.8A draw at 9V. If the lumens bin is actually S2, then the drive current could be closer to 2A and Vf about 3.2V, giving

0.85*7.4V*Ibatt = 2.0A*3.2V = 6.4W

Now Ibatt calculastes to 1.0A.

However, the point is that any reasonable set of assumptions gives a battery current draw of around 1A. If your 18650s can't hold their voltage at that draw, then you need better quality cells.


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## lemlux (Jan 18, 2012)

JustinCase:

The 2.8A delivered to the LED is for the Nailbender. I did not calculate the current delivered to the Malkoff but agree with you that it is likely to be less than 2.8A.

I'm happy to accept your contention that the Malkoff will work fine with newer batteries. Note my other comment in post 57 that 3S weaker older 18650 batteries (read sag prone batteries) are used in a light with an MN61 and older SF turbohead to avoid significant overvolting to the MN61. 

The linked thread asserts that the following differences in current draw occur with the MN60 and MN61 LA's when driven by 4S primaries and 3S Li-Ions, respectively.

"Surefire M4 "Devastator" 12V
MN 60 M4 LOLA -1.48A (1.65A on 3 Li-Ions) 20W
MN 61 M4 HOLA -2.51A (2.85A on 3 Li-Ions) 32W"

(MN60 current delta is 0.17A while MN61 current delta is 0.34A - twice as much using whatever reference 18650's were used.)

http://www.candlepowerforums.com/vb...urrent-draw-SF-amp-other-brands-incl-hotwires

When I use [email protected] "tired 18650 cells" the brightness is equivalent on an MN61 to that provided by 4S primaries suggesting that the combination of voltage sag and current delivery capability approximates that of primary cells. The voltage sag on primaries when using the MN60 is enough lower than that with the MN61 that I can use full strength 18650's without prematurely burning out the LA. 

Ergo, my assertion that my tired 18650's sag significantly while delivering something in the neighborhood of 2A to 2.5A.


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## Justin Case (Jan 18, 2012)

Those numbers are all well and good, but they are irrelevant. You simply won't draw that much battery current with the MD60. It clearly uses a buck driver and the battery current draw will scale with Vbatt/Vf.

As I wrote before, if anything the nailbender tower is *less suited* to 2S 18650 than the Malkoff MD60. Because the MD60 lower voltage limit (presumably for full regulation) is 6.5V, when each cell reaches ~3.2V under load, the light will start to dim because it has fallen out of regulation. This is an indication to change our your cells and serves as an excellent visual indicator to protect your cells from overdischarge. At that Vbatt level, Ibatt might be an estimated 1.2A-1.4A. Pretty mild draw -- around 0.5C for your typical 18650 these days.

In contrast, at the nailbender tower's min voltage of 3.4V, you will basically run down your cells until they croak or the cell's protection circuit trips to protect against overdischarge. That is far less kind treatment to Li-ions.

Edit: I want to clarify that I personally don't find either tower specs to be a hindrance wrt using 2S 18650 and I would be comfortable owning and using both products. But you have to understand the impact of the specs operationally. A low driver voltage to stay in regulation is great if you want to have the flexibility to use 1xLi-ion as well as multiple Li-ions. The nailbender tower looks like it is very suitable for that, while the MD60 is not. However, when it comes to 2xLi-ion, the Malkoff is the more forgiving product IMO because of the reduced likelihood of overdischarging the cells. But that also depends on your usage pattern. If you use your light for some known amount of time per day, for example, then it should be relatively easy to keep track of run time and re-charge the cells periodically to avoid overdischarge. But if you are not so diligent or it is not so convenient to track run time, then you have to assess whether this is an important issue or not and factor that into your selection criteria.


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