# 250 Lumen Cree R2 "Drop-in" for the M3



## donn_ (Nov 22, 2008)

Ok...it was a little more work than a true drop-in, but if I can do it, anyone can.

A short time ago, I spent a little time cranking the stock bezel rings off two M3 heads (Z46). This involved a heat gun, strap wrench and one of RPM's removal tools. All in all, it was pretty easy, and I love RPM's Ti bezel rings on the M3.

A day later, I read how Sgt LED installed a D26-sized LED drop-in in his M3, and I decided to try it with a new Lumens Factory D36 Cree R2 drop-in.

Off came one of the Ti bezel rings, and everything in the head...including the stock reflector, the reflector collar, lens gasket and lens.







I put the shock-isolation foam strip back in place, started the drop-in into it from the front, and used the reflector collar to shove it down into place inside the foam.






Once the drop-in is secure, simply re-install the reflector collar






Then the lens gasket






the lens






and the bezel ring






Now you have a nice 250 lumen Cree R2 M3!






A couple of notes:

The spring set on the drop-in is a bit shorter than stock, so I used a 1/16" magnet spacer behind the cells to make contact.

In the removal of the stock bezel ring, I scratched the Pyrex lens. Surefire won't sell these lenses, so I had to find a substitute for the 37.5 x 3.25mm stock lens. Otto Frei's website sells a watch crystal in mineral glass, which is 37 x 3mm for $3.50 plus shipping. It works just fine! 

There are other D36 Lumens Factory lamp assemblies which will work just as well, including an incan putting out 700 lumens.


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## Eric242 (Nov 22, 2008)

opNow that´s a nice mod - makes me think about getting a M3 again! I guess the tough part is the removal of the stock bezel without the RPM tool.

Eric


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## rtt (Nov 22, 2008)

Thanks for the detailed steps on this mod with pictures. Great job! Makes me want to get another M3:naughty:.


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## brighterisbetter (Nov 23, 2008)

Nice job on that one, now make sure to post your pics in the M3 mods and builds thread.


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## yazkaz (Dec 11, 2008)

So where can I buy the RPM Ti bezel rings and removal tools?


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## donn_ (Dec 11, 2008)

Here:

https://www.candlepowerforums.com/threads/192432

It looks like all he has left is plain, non-crenelated copies.


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## Sgt. LED (Dec 12, 2008)

:thumbsup:


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## divine (Dec 12, 2008)

Nice work, Donn!


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## Youfoundnemo (Dec 23, 2008)

sweet, and mark (lumensfactory) said that there was no reason to make IMR D36 dropins:shakehead if IMR D36 dropins were made Im pretty sure they would be in the 900-1000 lumen rangeoo:


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## donn_ (Dec 23, 2008)

He's probably right...so far. The only uses I can think of for them would be this head, and FM's 2 and 3x18500 D36 lights. They'd have to be fiddled with to run the current IMR cells. You could do 3x IMR 123s in the 2x18500, and 2x IMR 18650s in the 3x18500.

Overall, there aren't many of the FM lights out there, and not many people are doing the M3 head mod.


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## donn_ (Dec 23, 2008)

Youfoundnemo said:


> ...900-1000 lumen rangeoo:



You could hit that level in a reflector/bi-pin D36, or a bi-pin tower for the M3.

HEY FM!!


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## Eric242 (Dec 31, 2008)

It´s done:

http://www.ea242.de/pic/lampen/surefire-*******-02.jpg

http://www.ea242.de/pic/*******2.jpg

Unfortunatelly my D36 dropin is waaay dimmer than my LF D26 drop-in. 
I guess I´ll have to contact them since they should be about the same brightness. Both drop-ins are regulated R2, powered with 2x 3,6V rechargeables and the D26 is much brighter. I´ll have a comparsion beamshot up soon.

Eric

Edit:
http://www.ea242.de/pic/*******beam.jpg


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## KDOG3 (Jan 1, 2009)

Wait a minute, wait, wait wait! My head is spinning here. Isnt' the reflector PART of the head? As in one solid piece? How are you guys installing these modules through the front? More info please! I've always wanted an M3 but there wasn't an LED "tower" etc available. This is way cool. I just heard my wallet groan....


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## donn_ (Jan 1, 2009)

Kdog...when I opened the head, I took out the stock reflector assembly, and replaced it with the D36 drop-in. It has a much better reflector than the stock model. Once you open the head, and remove the shock resistance foam, the reflector assembly just drops right out.


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## KDOG3 (Jan 1, 2009)

SWEET. I was going to get an Optimus, but I may have to get one of these instead. Best place to get D36 drop in?


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## donn_ (Jan 1, 2009)

Eric..it looks to me like the hotspot in the D36 is just as bright as the D26, but smaller. That's what I'd expect from a larger reflector.


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## donn_ (Jan 1, 2009)

KDOG3 said:


> SWEET. I was going to get an Optimus, but I may have to get one of these instead. Best place to get D36 drop in?



Direct from Lumens Factory, or from Lighthound.


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## KDOG3 (Jan 1, 2009)

Cool. I wonder what the runtime would be off of 2x17500s? C'mon payday! LOL!


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## Eric242 (Jan 2, 2009)

donn_ said:


> Eric..it looks to me like the hotspot in the D36 is just as bright as the D26, but smaller. That's what I'd expect from a larger reflector.


Donn, that white wall beamshot is a little deceiving, here´s an outdoor shot I just took with my three Lumensfactory LED Drop-ins: a regular D26, a 3.7V D26 and the D36 OP. All cells fresh from the charger (1x17670 on the 3.7V D26, 2x RCR123 for the other two).






Eric


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## donn_ (Jan 2, 2009)

This beam shot makes it look like your D36 is defective.

I have one D36 OP, and it has a definitely smaller and brighter hot spot at short range, and a much longer throw. The tint makes a difference, as can be seen it this beam shot, but your D36 is definitely dimmer.


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## Eric242 (Jan 2, 2009)

Good to know you find it dimmer too - sometimes it is hard to catch for the eye like in my white wall beamshot - especially with such different tints. I just PMed Mark.

Eric


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## KDOG3 (Jan 2, 2009)

Question. Would Lighthound or LumensFactory be able to pre-test one so I can be sure I get a warm tint? I can't stand getting one thats blue again.


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## KDOG3 (Jan 6, 2009)

Bump for an awesome thread. My only concern is the cost - The M3 plus the head will be about $35 more than the Optimus which is due out anytime, which is the other light I was looking at. However, I can use rechargeables with the M3/D36 setup and we can correctly guess the Optimus won't. And the M3 parts are interchangeable......And the M3/D36 has the nice reflectored beam and the Optimus has the optics that I'm not to crazy about having experienced their other optics......Hmmmm I think the M3 setup is worth the cost.


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## donn_ (Jan 6, 2009)

You don't have to buy a whole new M3. The head (Z46) can be had for $53 + shipping, and you can put together the body and tail of your choice by watching the marketplace.


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## KDOG3 (Jan 7, 2009)

Ok, will the M3 head fit on an M4 body? If so, I'm in business!


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## Sgt. LED (Jan 7, 2009)

Yes this is what I use.


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## KDOG3 (Jan 7, 2009)

Excellent, so thats another option I have. Thanks for the info guys!. Where can I get an M3 head? I'll search. By the way, are there any pics of the M3 head on the M4 body?


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## Sgt. LED (Jan 7, 2009)

Contains LED mod that inspired Donn_ to try the D36.


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## donn_ (Jan 7, 2009)

Here's one on a 2x18650 Leef tube with an SW01 "Slim" tail.


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## KDOG3 (Jan 7, 2009)

Sgt. LED said:


> Contains LED mod that inspired Donn_ to try the D36.




Thats" what I'm looking for....I think I might wait until SHOT to see if Surefire is coming out with anything different in the M-series, like black HA (drool), grip ring on the M4 body ( I don't know WHY they never did that ), etc.... Can you imagine a black HA M4 with grip ring? That would just be the


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## Boltgun (Jan 7, 2009)

I said the same thing about the M4....sorry it isn't black but it is HAIII










I have a couple of spare bodies if you want one - send a pm

I just tried the D36 drop in and it isn't working - need to fiddle with it more

Boltgun


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## pee10755 (Jan 12, 2009)

I want to modify a surefire M500A AR15 weapons light to LED. Do you think this would work on that light?


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## Boltgun (Jan 12, 2009)

they have the same bezel, so it should work theoretically. 

Boltgun


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## chewy78 (Jan 18, 2009)

nice


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## Eric242 (Feb 1, 2009)

A few days ago I received the replacement for my defective D36 OP dropin. The new D36 is a mirror finish module and works the way it is supposed to.

comparsion beamshot with my LF D26 and defective D36:





now with the new mirror finish D36 dropin:





And just for fun again with a KL3-BK-BL:


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## KDOG3 (Feb 1, 2009)

Wow that mirror finish really gives it some throw! I have the OP coming from lighthound. I got the whole light together and I'm just CHOMPIN' at the bit for the LED head to come in. I'm thinking of just getting a MC2S switch (60 ohm) to install in the tailcap so I can have a low with it. We'll have to see...

Can I ask if the pill itself is the same size as the P60 sized drop-ins?


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## BSBG (Feb 14, 2009)

I just did one with the drop in courtesy of KDOG3 .

After a couple of less than perfect tries, I realized the stock foam wasn't going to work. The stock M3 reflector has a groove to hold the foam, just like the plastic retainer on top. I could not force the dropin down far enough with the foam in place, and the foam was too wide to put in after. A few snips off my toolbox liner foam, about 2mm narrower than the SF piece fit in after the drop in and allowed all the pieces to go together fine. No contact issues with any SF body, but a Leef requires loosening the head 1/4 turn to light - go figure.

Output seems reasonable and it runs on anything from one Li Ion to 4 CR123s in an M4 tube :thumbsup:.


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## donn_ (Feb 14, 2009)

:goodjob:

I'm running mine with a SW01 Baker's Cap, with an AW Soft-Start 3-Level switch. It works with the LF drop-in just fine!


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## Thundar (May 3, 2009)

I just joined this forum and am not familiar with all of the technical jargon, so I apologize if I sound like a doof. I am in law enforcement and have used my Surefire M3 at work for the past few years and have always loved it. I was very surprised during a search, however, when a newer officer lit up half a parking lot with his 225 lumen Fenix LED (TK10 or TK11) that cost him $70, while my $200(+) M3 put out only half that illumination. As I really want to keep my M3 as one of my carry lights I am trying to convert it over to a more illuminating LED that gives me at least the same runtime. For info: I use 3 Surefire CR123 batteries and have the original standard switch. 

4 questions regarding dropping in a Lumens Factory D36-MF LED: 

1) What kind of runtime will I get?
2) What is the actual lumen output for the M3 with the D36? 
(I know the Lumens Factory website says 250 lumens, but in another post on the forum members stated that the lumen output for the eo/ho incandescent bulbs for the M3 were approximately 0.50 to 0.65 of a Surefire measurement and I don't know if that applies to the LEDs as well).
3) Will the drop in be as rugged as the stock bulb/housing?
4) What will I need to buy anything else along with the drop in? Bezel removal tool, etc.

Sorry for the uber-long post. 
Thanks in advance for any help...


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## Justin Case (May 3, 2009)

If you drive the M3's MN11 lamp with two IMR16340 cells, you can get an estimated 300+ lumens. To do this, get an OpticsHQ M to E adapter, a SureFire E2 or compatible body and tailcap, and two AW IMR16340 Li-Mn rechargeable cells. Put the MN11 into the Z46 bezel, put the Z46 bezel on the M to E adapter, drop the IMRs into the E2, and thread the adapter onto the E2 body.

This is the result:










AW is a well-known battery dealer in the CPF Marketplace. His IMR cells are a type of Li-ion rechargeable that can deliver very high current (his IMR16340 cells are rated at over 4 amps, whereas regular Li-ion rechargeable 16340s can deliver only about 1A safely). OpticsHQ is a flashlight and tactical gear dealer. Check the CPF Marketplace Dealer's Corner. They have a coupon code for a discount. You might be able to find a two-cell E-series compatible body/tailcap made by FiveMega in the CPF Custom B/S/T forum. 

Another possibility is to keep the M3's 3-cell body but use only the two IMR cells and fill the last cell with a spacer. If you use Google to search for a 123A spacer, you should find a couple of sources -- IIRC OpticsPlanet and either BatteryJunction or BatteryStation.


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## Thundar (May 3, 2009)

Justin, that output is great. What kind of runtime would I get with 2 AW/IMR16340 cells and the MN11 lamp? Also, would the Ultrafire 3.6 volt or 3 volt RCR123 Lithium Battery Charger be a good choice to charge these cells?


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## donn_ (May 3, 2009)

If you can wait a few weeks, member nailbender will probably be offering D36 drop-ins with MC-E emitters. This will work exactly like the R2 installation did, but will be much more powerful.


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## Justin Case (May 3, 2009)

Thundar said:


> Justin, that output is great. What kind of runtime would I get with 2 AW/IMR16340 cells and the MN11 lamp? Also, would the Ultrafire 3.6 volt or 3 volt RCR123 Lithium Battery Charger be a good choice to charge these cells?


 
I need to check my spreadsheet for the tailcap current draw to estimate run time. But my guess is "short". Perhaps on the order of 10 min. Also, being an incandescent, lumens will steadily drop vs. time, down to maybe 170 lumens at the end. My SF "lego" produces a beautiful beam, but you just can't expect LED run time performance.

The Nailbender drop-in mods using a P7 or MC-E in direct drive will show a similar steady drop in lumens. The difference is that the LED is more efficient, so will probably last an hour on an IMR16340. Initial lumens can be high, say 700 or more. End state could still be 300 lumens before rapid dropoff. These MC-E/P7 numbers are a bit of a WAG, so don't pin too much on it for your decisionmaking. I am also ignoring heat generation, which can be a significant issue for these high-powered LEDs. For your M3, you need to run a single Li-ion cell for direct drive of an ME-E or P7. That might mean using an IMR18650 and one 16340 dummy spacer to get better run time than one IMR16340 and two spacers. But you will also need to get your M3 body bored out to fit the 18650.There is no free lunch.

If you are able to use a KT4 TurboHead with your M3, then there are some other very capable options. But you have to be willing to accept the large size of the KT4.


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## Justin Case (May 4, 2009)

I measured 2.6A tailcap draw using 2xIMR16340 cells to drive the SF MN11 lamp. If we assume 500mAh capacity, the run time looks like about 10 minutes. Possibly too short for your purposes.

Hot spot lux at 1 meter measured 11,000 lux. In comparison, a Deal Extreme SKU 11836 R2 P60 drop-in measured about 7000 lux.


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## Thundar (May 5, 2009)

It sounds like converting to LED is the best way to go to increase lumen output AND keep or increase runtime. Was the 250 lumen output listed by Lumens Factory comparable to similar outputs listed by Surefire? 

Along that line, what kind of lumen output and runtime would 2 AW/IMR16340 cells (and spacer) + the LF D36 drop-in produce?


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## Justin Case (May 5, 2009)

Just for completeness, I measured 2.4A at the tailcap when driving the MN11 lamp with 3xSF123A primary lithiums. I also measured about 7600 lux at 1 meter for the hot spot. At this current level, SF123A cells have about 0.8Ah capacity. So theoretically, calculated run time might be about 20 min, which is exactly the run time that SureFire advertises.

When using the SF cells, the MN11 is driven at about 14W. When using the IMR cells, the MN11 is overdriven at about 20W which probably cuts the lamp life.

So for ~50% increase in lumens output and in hot spot lux, you get about 50% of the run time and some unknown decrease in lamp life.

If you can go with a 4x123A tube length, then you can run 2xIMR18650. These cells are rated at 1600mAh, giving a calculated run time of about 36 min.

If you can obtain one of FiveMega's 2C cell SureFire head and tail bodies and get it bored out to fit the AW IMR26500 cells (LiMn C cells), you might get 50 min calculated run time.


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## Thundar (May 6, 2009)

Again, it sounds like using the MN11 lamp will really cut down on runtime... 

What kind of lumen output and runtime would the LF D36 drop-in produce with:
..... 2 rechargeable AW/IMR16340 cells (and spacer)?
..... 3 SF 123A batteries?


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## Justin Case (May 6, 2009)

You can calculate estimated run times using some judicious assumptions.

This is the key equation for regulated LED lamps:

% driver efficiency * Vbatt * Ibatt = Vf * If

For an R2, we might assume 3.7V for Vf at If=1000mA (1A). For 2x16340 rechargeables, Vbatt is probably about 7.4V. For 3xSF123A, Vbatt is around 8V. Also, let's assume an average driver efficiency of 80%.

For the 2x16340 case, we get Ibatt = (3.7V*1A)/(0.8*7.4V) = 0.63A. For the 3xSF123A case, we get Ibatt = 0.58A. Let's call it 0.6A for both cases.

The capacity of a 16340 Li-ion is about 500mAh. The capacity of an SF123A is around 1400mAh. Thus, the estimated run times for 2x16340 and 3xSF123A are about 50 min and 2.3h, respectively.

If the R2 LED's Vf is lower than 3.7V, run time increases. You can plug and chug with your own numbers to do a sensitivity analysis. If Vbatt is higher, run time also increases. Maybe you want to use 7.6V for 2x16340, or 8.25V for 3xSF123A. I think this is nibbling at the edges, but it can be a useful exercise to see how sensitive these calculations are to small changes in the assumptions.


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## Thundar (May 6, 2009)

50+ minutes sounds pretty good to me. How about lumen output?


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## Justin Case (May 7, 2009)

Like the subject line says, 250 lumens (at the emitter).


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## Sgt. LED (May 7, 2009)

Thundar said:


> 50+ minutes sounds pretty good to me. How about lumen output?


 
Just about the same as your buddies Fenix. You focus will be different though. You will be using a larger and possibly deeper reflector so your spill will be wider and I think your hot spot will throw further.

Was his light an OP reflector or smooth, and which reflector are you going to order?


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## Thundar (May 7, 2009)

I really don't know what his reflector was. I am ordering a "Lumens Factory D36-LED Mirror Finish Reflector 3.6-13 volt 250 Lumen Lamp" as we speak. 

Do I need to purchase any special tools to take the head assembly apart?


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## Owen (May 7, 2009)

I didn't need tools. Maybe a couple of rubber jar openers to help get a grip on it. Put it in a ZipLoc bag in boiling water for a couple minutes. I just pressed the crenelations into the palm of one hand, and turned with the other. Lay everything out in the order you removed it, and put it back in in the same order after removing the reflector.
It took a few tries for everything to work, for whatever reason. If you've got the foam shock isolation band flat against the inside of the head you should be able to force the D36 module in.

Lumens Factory should be coming out with their SF C series compatible head for D36 lamps and LED dropins(check their site under new products) soon if you don't want to take apart your Z46-M3 bezel.


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## Sgt. LED (May 8, 2009)

That new head looks awesome too. :thumbsup:


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## Thundar (May 10, 2009)

Soooooo, I got the LED in in First Class mail today. Lighthound shipped it out FAST (I ordered it Thursday and got it Saturday)! I put it all together and it won't turn on. The button on the tailcap switch doesn't really depress. I checked the tailcap switch by trying it out on my Z2 and it is functioning fine. The Z2 tailcap switch has the same issue on the M3 body. The batteries seem to sit too far down in the body as if the spring on the LED is too short. I tried to unwind the spring a little and get it to stick out farther to no avail. 

Any ideas how to make this work without breaking the spring off the LED housing?


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## Eric242 (May 10, 2009)

You´ll need to use a spacer magnet between the cells. And just in case: It might be possible if the light is dropped the spacer could shortcut the batteries/LED when touching the inner wall of the battery tube. To prevent this you should wrap the spacer with tape so that it´s sides won´t be able to have direct contact to the body.


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## BSBG (May 10, 2009)

What battery set up are you using?

Will it turn on if you short the tail end with a paper clip?

It took me a few tries to get it right, and I had to cut a new piece of foam to get it 100%.


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## Thundar (May 10, 2009)

I'm using 3 SF 123A's. 

Any specific type of magnet spacer?


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## Justin Case (May 10, 2009)

deleted


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## Justin Case (May 10, 2009)

It's not clear to me that magnetism is required, although it may help prevent movement of the spacer (depending on spacer dimensions). Examine how much of a gap you need to take up and maybe you can find a metal object of approx 15-16mm diameter and the right height to use as a spacer. I would tape or coat the outside of any metal spacer with electrical tape or other insulation to prevent shorts. Keep the overall diameter less than about 17mm and everything should fit in the SF tube. I would also torture test the new setup before trusting it for duty use. Shake it, bump it, rap it against your hand, run it upside down, mount it to a weapon, etc. Make sure it never cuts out,fails to function, or shorts out.


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## Thundar (May 11, 2009)

Man, this is becoming much more complicated than I had first anticipated. 

Will one of these spacers on the lighthound site would work?

Magnetic Spacer for Charging 1/4" x 1/4"
http://www.lighthound.com/Magnetic-Spacer-for-Charging-14quot-x-14quot_p_1047.html

Or

Magnetic Spacer for Charging CR2 or 14250 Battery (1/4" x 3/8")
http://www.lighthound.com/Magnetic-Spacer-for-Charging-CR2-or-14250-Battery_p_1048.html

I am concerned that the magnetic spacer is so narrow that it will come loose from the battery, go sideways in the body and touch the inner wall. 

Are there any other options or should I just order one of each and give them a try?


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## Thundar (May 11, 2009)

...figured out the quick reply btw...


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## Thundar (May 11, 2009)

For further: I am planning on ordering 2 rechargeable AW/IMR16340 cells along with a dummy 123A cell in the future. Will these magnetic spacers cause a problem with that setup?


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## donn_ (May 11, 2009)

There's little or no reason for this to be complicated. I indicated in the initial post the spring was shorter than the stock setup, and a spacer was required.

I only needed a 1/16" spacer, and I doubt you'll need 1/4" or 3/8". You can make a perfectly good one, custom fit to your needs, by stacking the appropriate number of metal washers, or even a penny or two. Tape the outside with electricians tape to avoid shorting against the inner wall of the flashlight.


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## BSBG (May 11, 2009)

Thundar said:


> For further: I am planning on ordering 2 rechargeable AW/IMR16340 cells along with a dummy 123A cell in the future. Will these magnetic spacers cause a problem with that setup?



You would be much better off with 2 17500s with the LED module - double the run time.


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## Thundar (May 11, 2009)

OK, I tried to tape together a bunch of little metal washers together to connect the circuit and the light flickers on and off... I do love the amount of light and throw of the LED when it does work, however. I am ordering some rechargeables tonight along with a magnetic spacer. 

My understanding regarding the three types of rechargeables that I've read about so far is:
AW IMR16340's - put out more light/current than lithium SF 123A's, with a similar runtime (approximately 50 vs 60 minutes). They require a dummy spacer to fit into the same body.
AW 17500's - longer runtime than lithium SF 123A's. 2 take up the place of 3 123A's. 
AW 18650 - not really an option for me as I don't want to bore out the body. 


2 questions: 
1) Will the two AW IMR16340's burn out the LED or cause some other problem due to the high amount of current? 
2) Will the two AW 17500's put out roughly the same light as SF 123A's?


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## Justin Case (May 12, 2009)

I don't know what kind of magnet you are going to buy, but be aware that the shiny Ni-plated neodymium magnets are very brittle. I've had several break in half just looking at them cross-wise. One broke right in my hand as I was handling it. I personally would not trust them in a flashlight. My belief is that under impact (e.g., dropping the light), these magnets are highly susceptible to fracture.

The IMRs have higher current capacity than the regular Li-ions, and also lower internal resistance. But I doubt either one is an issue driving the LF R2 lamp. You should get the same output using any of the battery combinations listed, assuming the LF R2 lamp is running in regulation.

I'd be surprised if 3xIMR16340s give you longer run time than 3xSF123A cells.

Let's say that the LF lamp driver is 80% efficient. Let's also assume that the IMRs run at 3.8V each under load, vs 2.6V each for the SF123As. If the R2 forward voltage is 3.7V at 1000mA, then 0.8 * 11.4 * Ibatt = 3.7, and Ibatt = 3.7/(0.8*11.4) = 0.4A. In comparison, for the SF123As, Ibatt = 0.6A.

But the IMR capacity is about 500mAh vs 1400mAh for the SF123As, giving estimated run times of 1h15m vs 2h20m, respectively.

It's hard to see a likely combination of variables that would increase the IMR run time by a factor of 2 to surpass the SF123As.

Let's look at the 2x17500 case now: 0.8*7.6*Ibatt=3.7, and Ibatt=0.6A. AW rates his 17500s at about 1100mAh capacity, so you'll get a little less run time vs 3xSF123As. About 1h50m.


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## Thundar (May 12, 2009)

I was planning on getting a 1/4" x 3/8" nickel plated neodymium disc magnet from lighthound. 

Would a 15mm Charging Spacer made out of Aluminum work?


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## Justin Case (May 12, 2009)

Any chunk of metal of the right dimensions will work. Then tape, shrink tube, paint, etc the sides like it was a small battery, to insulate it from shorting against the flashlight body.


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## DM51 (May 12, 2009)

Thundar said:


> ... I tried to tape together a bunch of little metal washers together to connect the circuit...


Er… this sounds a bit iffy… I wouldn’t be too happy with the idea of these metal washers just held together by tape… 




Thundar said:


> I was planning on getting a 1/4" x 3/8" nickel plated neodymium disc magnet from lighthound.


Good quality neodymium magnets are extremely strong. You could have a problem managing one that size.




Justin Case said:


> Any chunk of metal of the right dimensions will work. Then tape, shrink tube, paint, etc the sides like it was a small battery, to insulate it from shorting against the flashlight body.


This is a better idea, although please do NOT rely on paint as an insulator – it will not be safe.


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## Owen (May 12, 2009)

Thundar said:


> 2 questions:
> 1) Will the two AW IMR16340's burn out the LED or cause some other problem due to the high amount of current?
> 2) Will the two AW 17500's put out roughly the same light as SF 123A's?


1)No. They have nothing to do with the amount of current going to the LED. Unlike incandescent lights that are driven directly by the batteries, this drop-in has a "buck" circuit that controls the amount of current, and lowers the input voltage to that of the emitter. These batteries are not a good choice for most LED setups, with the exception of those with high current requirements that are beyond the ability of standard Li-ion cells of similar size. You will be better off with the regular protected cells, as they have higher capacity in addition to being protected.

If you're using the 6-13V Lumens Factory drop-in with the stock M3 body, I would think your best bet is to use 3 R123 or 2x17500. The total capacity will work out almost the same, but 2x17500 will be more convenient to charge and load, and cheaper to buy. 

2)Brightness should be the same, because the drop-in is regulated. Protected 17500s will provide full output until they abruptly cut off as one or both of their protection circuits kick in when the voltage is low enough, though, while 3x123 will run longer then continue to function with rapidly decreasing brightness after falling out of regulation. Same would be true for 3 protected R123s as 2x17500.


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## Thundar (May 13, 2009)

Well, early yesterday I ordered 3 different length (1.6mm,1/4",3/8") magnetic spacers, a 15mm aluminum spacer, 2 AW IMR16340's, a 123A dummy and a battery charger (Ultrafire 3.6 or 3 volt). 

I ordered the aluminum spacer just in case the magnetics don't work, and I will file it down to an appropriate size and then insulate the sides with electrician's tape. I ordered the 16340's because I like the idea of having rechargeable replacements that I can use in my other lights as well as my M3 (my gun light and Z2). 

I will advise how it turns out.


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## Thundar (May 14, 2009)

I got the spacers and rechargeables today. Both the 1/4" and 3/8" worked perfectly size-wise. The light still flickered, however. I took the head back off and noticed that the heavier spring (the one that puts pressure between the head and body) was not attached to the LED housing but was floating free. I attached it back on the housing and tried again - SUCCESS! The beam is pretty narrow, but that's fine. I like the throw and intensity of the beam. 

My next mod will probably be to my Streamlight SL20X, but not for a little while. 

Thanks for all of your help!


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## Thundar (May 14, 2009)

BTW, I covered the sides of the magnet with electrician's tape to avoid short circuiting the light. Justin, the 1.6mm magnet broke in half as I was taking it out of the bag, but the 1/4" and 3/8" magnets seem pretty durable. They sure do have strong pulls.


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## allburger (Jun 1, 2009)

Has anyone considered or experienced any heat dissipation issues with this set up?


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## Justin Case (Jun 2, 2009)

Just to update the estimated output of an MN11 lamp when driven by 2xIMR16340, it looks like it could be somewhere north of 380 lumens, based on testing of a P91 lamp:

https://www.candlepowerforums.com/threads/233057


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## TigerhawkT3 (Jun 2, 2009)

allburger said:


> Has anyone considered or experienced any heat dissipation issues with this set up?


+1

What's the thermal path like between the drop-in and the body?


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## allburger (Jun 2, 2009)

I opened the head on my m3 yesterday and have a lumens factory d36 op on order. I guess i can be the test dummy for the heat issues. I guess i ought to be since i asked the question and I'm running the led in there regardless!!!!


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## Sgt. LED (Jun 2, 2009)

Hey fellas!

So far I've not cooked my rig. Thermal path is not great though. I think it takes a bit too long for the head to warm up. I think finding just the right diameter aluminum collar to bridge the gap from drop-in to the head would do wonders but at this point I've not found anything that fits just right. Again so far I have not damaged anything.

It's so easy to swap the emitter I am not really worried about it. I know not everyone is into emitter swapping so the hunt for the solution will continue.

Anybody got any further ideas to bridge the thermal gap?


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## donn_ (Jun 3, 2009)

I haven't had any problems either, but I tend to only run this sort of light for a few minutes at a time.

As Sarge said, there isn't much of a thermal path. The reflector is isolated from the head by the foam anti-shock strip, and the pill doesn't contact the body, other than through the spring.

I'm thinking about two solutions. One is to replace the foam with a metal collar. I don't need anti-shock, and it might move some heat from reflector to head. The other is to coil bare copper wire around the pill, so it contacts the inside of the body. This would essentially replace the spring, and provide both current path and thermal path.


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## Policetacteam (Jun 4, 2009)

Ok...so while we're on the topic of legoing the M3 head...will it fit on a M2 body? This thread is very cool. I may need to just buy a whole new M3. I have kind of always wanted one and this is a great excuse for purchasing one!


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## Justin Case (Jun 4, 2009)

The Z46 bezel from an M3 most likely won't fit on the M2, without some sort of adapter. The M2 uses the classic threading from the 6P, as indicated by the fact that it can use the KT1 TurboHead. The M3 uses Millennium threading, as indicated by the fact that its TH upgrade is the KT4.

An update on the output of the P91 lamp when driven by 2xAW17670 Li-ions in a SureFire 6P host plus Solarforce extension tube and using a UCL window -- 466 lumens on startup. The M3's MN11 lamp should perform similarly. If you want to stick with the M3's form factor, then use 2xIMR16340 cells (though you sacrifice run time vs the bigger 17670s -- probably about 10 min vs 30 min, as I had calculated in an earlier post in this thread).

Now that I think about it, it may be possible to take an AW Turbo Tower, and cut it down to the right height to emulate an MN11 lamp assembly. From the wide flange down, an MN11 looks the dimensionally same as something like the MN21. I will check this out tomorrow. If this is the case, then cutting down an AW tower should work, and that would allow you to build an LED tower that can run in the stock Z46 bezel of the M3. You could run emitters like a Seoul P4, Luxeon K2, or even a Cree MC-E.


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## donn_ (Jun 5, 2009)

Justin Case said:


> Now that I think about it, it may be possible to take an AW Turbo Tower, and cut it down to the right height to emulate an MN11 lamp assembly. From the wide flange down, an MN11 looks the dimensionally same as something like the MN21. I will check this out tomorrow. If this is the case, then cutting down an AW tower should work, and that would allow you to build an LED tower that can run in the stock Z46 bezel of the M3. You could run emitters like a Seoul P4, Luxeon K2, or even a Cree MC-E.



It would take more than simply shortening the tower.







On top is an AW Turbo Tower with a K2TFFC emitter.

On the bottom is a Turbo Tower with Rebel 100, built specifically for the M3 reflector assembly.

As you can see, the M3 tower is not only shorter, but substantially narrower, in order to pass through the reduced aperture of the M3 reflector. It's necked down twice, to provide a path for the wiring to the emitter.

To use a larger emitter, like the P4 or MC-E, you'd have to enlarge the aperture on the M3 reflector, as well as shorten the tower.


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## Justin Case (Jun 5, 2009)

Yeah, the problem is that the Z46 bezel necks down the reflector opening and the narrower opening is big enough to fit only the small bulb of the MN11 lamp assembly.

Here is a KT4 TurboHead on the left and a Z46 bezel on the right. The initial openings for both are the same, but the Z46 then necks down.





SureFire MN11 on the left, N62 in the middle, and AW Turbo Tower with 2S2P MC-E on the right. Note the skinny glass bulb for the MN11 compared to the larger bulb on the N62. Also note that the black aluminum base for the MN11 and N62 are the same diameter. Thus, as donn_ says, if you open up the necked section of the Z46 bezel to the same diameter as the upper section, a cut-down AW Turbo Tower should work.


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## donn_ (Jun 5, 2009)

Someone opened up the aperture of an M3 reflector, for a Turbo Tower. I just read it recently, but for the life of me, I can't find it now.


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## Justin Case (Jun 5, 2009)

I have this black anodized turbo tower to match the look of the MN11.


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## Thundar (Jun 20, 2009)

Soooo, I've been using my Cree R2 at work for about a month and it just stopped working. I know the LED is getting power because it illuminates very faintly when the tailcap is depressed. The LED isn't putting out enough light to reflect any observable reflection from the reflector, but you can see that it is on by looking directly at the LED. It started doing this a few days ago, and after taking the head off and manipulating the small spring, it would light up as normal. Now, I can't get it to light up. I've tried both my rechargeable batteries and my standard 123's and I get the same slight illumination.

Has my LED burned out or is there a solution?


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## Justin Case (Jun 21, 2009)

This is for a Lumens Factory LED module for the M3? And you used a magnetic spacer? Any chance that the spacer moved and shorted the inner and outer spring connections (I assume that the LF module has these -- I'm not familiar with the specific product)? I'd contact LH or LF and ask them what sorts of features their driver has, esp short circuit protection.

Can you smell anything burnt?

Can you measure the current draw at the tail?

If you are up to it, you probably can partially disassemble the module, assuming it is built like the usual P60 drop-in. Unscrew the pill. Desolder the driver LED- wire from the LED. Hook up a DMM in series with the LED- side of the driver (one DMM probe to the LED- wire from the driver, the other DMM probe to the LED- side of the LED) and put the DMM into amps mode. Apply power to the driver. Check the current output displayed on the DMM. Presumably, the current output from a working driver should be around 1A.


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## Thundar (Jun 22, 2009)

Yes, I have the LumensFactory LED module and a magnetic spacer. 

The magnetic spacer did not touch the side - it's rounded edge is covered with electrical tape and each time the illumination would drop I checked the battery configuration to ensure the magnet was secure. 

There is no burnt smell. 

I am not able to check the current at the tailcap or check the output on the DMM.

Can these LED modules burn out? I'm running 2 AW IMR 16340's with a dummy cell behind them. Could these have had too much amperage or something?


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## Thundar (Jun 22, 2009)

If the LED is burnt out, I was thinking about trying a high output incan lamp as I recently ordered another LED module for a 3D maglite that will have good runtime so I will only use the M3 for clearing rooms and the like. 

Which is a better incan lamp: the MN11, the LumensFactory HO-M3, or LumensFactory EO-M3? 
Are these all pretty sturdy? 
Are there any other options that I missed?

BTW: As this will probably come up, I lost the MN11 lamp that came with the light so would have to order it.


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## Thundar (Jun 22, 2009)

Just spoke with Lighthound where I ordered the LED. They said the battery setup shouldn't have blown the light. They said they've gotten a few D36's back and that they might have had a bad batch.


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## Thundar (Jun 22, 2009)

After all of my posts regarding not using the MN11 lamp due to it's low runtime, I may use it now. Initially, I used my M3 as my primary patrol light (and therefore needed long runtime) but now have more lights to use for different purposes on duty. I have a 220 Lumen Terralux for general use where I don't need extreme illumination. I got a new NiMH stick for my old SL20X (which will likely be a backup light that stays in my patrol car). I am also upgrading a 3D maglite with a 2100 Lumen ElektroLumens LED drop-in with NiMH D cell rechargeables. I will primarily use my M3 for building clearing due to it's high output and ease of use while holding my pistol. BTW: I blame this forum and all of you for my relapse in my flashlight buying addiction (I can stop anytime, of course). I may have to start a 12 step program...

Back to the M3... I'm using 2 of the AW IMR 16340's with a dummy 123 cell. From what I've read, the EO or HO-M3 lamps put out by Lumens Factory actually have less output than the MN11 lamp, so I think I'll go with the MN11. I wish I hadn't accidentally thrown out the one that originally came with the light, oops. Lighthound advised me that they can credit me for the malfunctioning LED (which will give me enough to get a MN11 lamp from them).


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## Thundar (Jun 26, 2009)

OK, I'm trying to put the MN10 (& MN11) reflector back in, but can't get it back in the shock isolation foam piece that loops around inside the head. The foam has started to tear in different places now. Every time I try to push the reflector inside of the foam the foam either bows in so that the reflector is above the foam and the foam donuts downwards, or the reflector is at an angle and one side begins to donut downward. I literally struggled with it for 2 hours yesterday. 

I thought about putting glue on the outside of the foam, maneuvering the foam in place and letting the glue dry before attempting to put the reflector in. I'm concerned with the combination of heat and the glue, however...

Any ideas on how to get this in?


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## Thundar (Jun 26, 2009)

Just realized I've kind of hijacked this thread... I'll restart on another thread still in the Homemade and Modified Lights section. Thanks for all of the help you have already provided.


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## Superdave (Jul 28, 2009)

Just an FYI for anyone doing this mod, it is (or was for me) extremely easy to remove the M3's bezel ring. 

I set the bezel onto a 2x4, crown down, then set another small block of wood on the back side. A few taps with a hammer sunk the crenelations into the 2x4. I then pushed down and twisted at the same time. Ring was 100% un-damaged and everything came out perfectly. 


and, now to wait another week or 2 for my LF D36 module to arrive :sigh:


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## Sgt. LED (Jul 28, 2009)

Cool, I bet the hammering helped weaken the Loktite too. Good job.


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## Superdave (Jul 29, 2009)

Thanks

there was a little bit of residue in the threads but not as much as i've seen from SF in the past. I might try this with my M6 today as well.


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## BugOutGear_USA (Jul 31, 2009)

FYI,

I just did this mod on my M3 today and wanted to let everyone know that you can remove the bezel quite easily with one of those watch back removal tools (purchased at Wal-mart for $5-$6).

What is everyone using as a spacer for the D36 module since it is slightly to short to make proper contact?

Regards,
Flavio


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## donn_ (Jul 31, 2009)

I use insulated rare earth magnets.


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## houtex (Jan 11, 2010)

Have to bring this thread back up....

I got the LF D-36 led drop-in today and am currently trying to install it. 
I got the head open and everything apart but I cannot get the LF to sit properly on the head. Worst yet, I tore the foam sponge strip.:mecry:

What can I do?!?!?!any idaes please.


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## BSBG (Jan 12, 2010)

I had to trim a piece of foam sheet a bit narrower than the stock piece to get mine to work. I used the drawer liner in my rolling tool box, can't remember where I got it but it worked perfectly.


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## bstrickler (Apr 8, 2010)

How well is this drop-in regulated? My D26 LF XR-E R2 dropin draws a constant 500 ma, no matter how many cells you have in it, which just wastes power.

Is it a better driver (current draw goes down, as voltage input goes up), or pretty much the same driver as the D26 version?

~Brian


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