# DIY How to build a p7 mag 2C for under $30.



## Seiko (Apr 12, 2009)

DIY How to build a p7 mag 2C for under $30.


Mods I was not sure if this belongs in the homemade lights section or here. So feel free to move it if needed.

The goal of this build was to make a 2 C Mag with a P7 for as cheap and easy as I could.
I am no electronics expert, just a few builds under my belt. So if you see something I have done wrong, don't hesitate to set me straight.

Parts needed.
Mag lite. I love the 2 C I think it is absolutely the perfect size in a hand held light.

From dealxtream sku 14413 ($27)

2 18650 lith ion batteries (I recommend AW protected)
Or the soon to be released AW 26500 (c size) protected

Now you have 3 options for the tail cap. 

Buy the 26500.

Orv if running 18650's I highly recommend you buy a Mag C ring Kit from Download on CPF 

https://www.candlepowerforums.com/threads/178764 It will save you alot hassle and is only $22 shipped.

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If you don't want to spend the money.... I am including directions on how to do this without the kit.

A piece of 1/2" Flexible PVC Pipe found in the sprinkler isle at Home Depot ($1) 
Made by Orbit marked 1/2" x 24" Flexible PVC Pipe

You will need a Split ring (like for keys), some bare wire, and a piece of camping sleeping pad or other piece of dense foam.
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Other misc parts, wire, solder, soldering tool, multimeter, Thermal adhesive, a few basic tools, allen wench a pair of pliers, razor blade, wire strippers/clipper, a dremel tool or hack saw.


On with the build!

Here is one slight problem that needs to be addressed. The drop in fits just fine, but sits too tall for the bezel to screw down with a lens installed.

You can either, run it without a lens, spend a few minutes with a dremel tool to take about 2mm off of the top of the "drop in", or have a friend with a lathe do it (that is my pick)








The drop in fits just about perfect inside the mag C body (new and old) almost as tight as a heat sink. A bit of thermal adhesive and you probably wont even have to use aluminum foil as a shim. Unless you leave the light running for a real long time (over 5-10 mins) I wouldn't even bother.









First step is to take your light apart. I wont go into too much detail here. Just pop off the button cover insert your allen key, and back the screw out. Slide the switch out the rear of the body. Then take that same allen key, and remove the other screw on the switch that slides up and down.







Now break out the dremel and cut off the top half of the switch. Remove the negative strip from the switch (just slides right out) before you make the cut. .







You are going to solder the positive wire to the center piece of metal and the negative wire to the strip that is standing up here.







Trim the negative strip down about flush with the top of the now cut off switch. and solder away.










OK Now reinstall the switch into the light. Make sure that you get it aligned correctly, and that the screw is centered properly in the detent. That is what makes the negative side of the switch work.

Ignore this part if running 26500, you will keep everything stock.

On to the tail cap!
Again I recommend the mag kit from download.... but here you go anyway.
You need to find a split ring that fits into the recess that the origional mag spring sits in. Shouldn't be too hard I found it at home depot in the key section. 

Take several pieces of bare wire and loop them through the split ring.






Then take the piece of dense foam, and cut it to fit in the bottom of the tail cap. This will need to be rather thin. You will have to play with this a bit depending on th 18650's you are using. It is what adjusts the tension on the batteries.

Now bend your wires down, and cut them to length. So it looks something like this.

*VERY VERY VERY IMPORTANT*, make sure that the batteries do not rub against the bare wire that is looped around the split ring. If it rubs through the shrink wrap it will cause a short circuit and other very dangerous side effects (like batteries exploding)








Now on to the battery tube.
Cut a length of the pipe, so that it sits just under the threads inside the flashlight body.
Split the tube down the side, and it will be absolutely perfect for fitting the batteries with no rattle, and no worry if your batteries are hitting the positive contact of the switch correctly.







Now I always test when I am at this juncture of a build. It will save alot of time troubleshooting if you just hook your multimeter up to the bare wires out the front of the light now.






So now we know that our soldering on the switch was fine, and our battery and tail cap mod is working as well.
So if we don't get light after soldering that together then we know it was either the driver installed on the "drop in", the LED, or our solder job.

So go ahead and screw the head onto the body and solder your connections together. The drop in comes with a spring attached to the base, but I went ahead and de-soldered it because it was not needed.

When using the same color wire, mark the negative side with a bit of black sharpie, so I don't solder it wrong on accident. I left my wires kinda long here, I know I will have to take it apart again so that I can just buzz it down a tad on the lathe so I can install a lens.






Now hit the switch!!!! Just for a second though to make sure it works. If it lights up go ahead and poke all your wires into the body. Apply your thermal adhesive around the outside of the drop ins base, and screw down the bezel. (notice the gap between the bezel and the rest of the head, due to the height of the drop in)






Now go enjoy your light!!!







If there is anything that you have questions let me know.
Total build time was around an hour, and that included a trip to radio shack because I was out of wire.
Hope you enjoyed it,
Bill 


Beam shots to follow shortly.... Have to wait till it is dark out.


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## LiteFan (Apr 12, 2009)

How is the runtime?


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## Seiko (Apr 12, 2009)

LiteFan said:


> How is the runtime?



Depends on the mAh of the 18560s you are running. But roughly 45mins -1 hour.


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## Gunner12 (Apr 12, 2009)

Nice!

If you don't mind, I'll add it to the Maglite drop-in and mod's thread.

I think the mods will move it to the homemade and modified section.


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## Seiko (Apr 12, 2009)

Gunner12 said:


> Nice!
> 
> If you don't mind, I'll add it to the Maglite drop-in and mod's thread.
> 
> I think the mods will move it to the homemade and modified section.



Sounds good 

Yeah I debated putting it in the homemade, but wasn't sure where it should go. Figured Id let DM51 decide for me LOL


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## kz1000s1 (Apr 12, 2009)

I've seen this module before, but I was concerned about it's heatsinking. I would like to know how hot it gets. One tip about modding the switch is that you don't have to cut off the brown bulb holder. You can separate the switch halves and it comes right out. If you do this you just have to be carefull about the little pieces on the ends of the switch spring.

I love the 2C also. I have a P7 with a D2flex driver in mine.


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## allburger (Apr 13, 2009)

When I opened up my C switch to remove the brown tower, the switch never seemed to go back to its self for me. I tried super glue to close it, but the spring pressure pops it open. This caused alot of headache for me, so on my current 2c p7 project, I decided to just cut the tower, like the op did


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## Seiko (Apr 13, 2009)

I am really impressed with this, it racks right up there with my mag 2C hotwire with a WA 1111 bulb (800-850ish lumen) Nice size hotspot real good flood perfectly center with no artifacts, or dark rings. Id say in the 700-750 lumen category.

All photos 
The lights all had fresh batteries and were taken within seconds of each other.
f3.5 1/30 800 ISO 


The angel is about 30 feet front the camera.
Stock 2C mag Duracell Alk batteries







P7 2C mag with AW Protected 2x 18650







Hotwire 2C mag WA1111 bulb with AW IMR 2x 18650








Really crappy white wall photos. I will redo these latter.

Stock 2C mag Duracell Alk batteries





P7 2C mag with AW Protected 2x 18650





Hotwire 2C mag WA1111 bulb with AW IMR 2x 18650


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## Seiko (Apr 13, 2009)

kz1000s1 said:


> I've seen this module before, but I was concerned about it's heatsinking. I would like to know how hot it gets. One tip about modding the switch is that you don't have to cut off the brown bulb holder. You can separate the switch halves and it comes right out. If you do this you just have to be carefull about the little pieces on the ends of the switch spring.
> 
> I love the 2C also. I have a P7 with a D2flex driver in mine.



It will not beat a real heat sink, but I think with a shim of maybe 1-2 thicknesses of aluminum foil and thermal adhesive it will be just fine, thats how tight it fits stock. 
I had this one running for 10 mins tonight on the dog walk, and it was a bit warm to the touch right in front of the switch, but not anywhere near where I would turn the light off for fear of damaging the emitter. Thats with no adhesive or shim. Its a stout reflector and pill. It will eat up alot of the heat there, never mind the transference to to body.

I hate taking apart the switches, can never get them to sit right back together once I have opened them. On the old style C they were not welded, so you can pop the front of real easy and snap them back together. (opps just noticed that allburger beat me to saying it  )


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## Benson (Apr 13, 2009)

kz1000s1 said:


> I've seen this module before, but I was concerned about it's heatsinking. I would like to know how hot it gets.



I've used the same reflector and pill (you can get them separately, DX sku.13803) in a D Mag, with a linear-regulator setup that should be dissipating at least as much heat as that, and only heatsinked through the reflector-head joint. Runs for 190 minutes in regulation, and the head gets warm, but not hot. Obviously running it outside of the Mag, just the bare reflector/pill, does get substantially hotter, but I've run it this way off a lantern battery for a half hour without it getting the pill getting too hot to hold onto, so in the light definitely isn't a problem.

In the flashlight, output does fall off up to 10% or so as it heats -- I suppose I could look up the output vs. T curve in the datasheet and turn that into some real numbers, but I'm too lazy -- I know it works fine, and that's enough for me.

BTW, regarding this mod, other battery options exist that could save you the tailspring work and get higher capacities; you could use 2x 25500 (DX sku.5035, but unprotected!), or better, AW's IMR26500 (safe chemistry, no protection needed), which should be available any day now. A really cool setup is to shorten and modify a C-Mag spring so that 18650s fit down through it (and make contact with copper-braid-on-foam), or it can contact 25500s directly -- this lets you use either battery setup, and is what I did with my Mag61.

As for the 2C thing, it's a great pocket light, but I prefer longer lights if I'm going to be walking around with them for long periods -- with a 3 or 4D light, you can let your shoulder take the weight, and carry the light at-the-ready for hours (and pick up hours of runtime as a bonus). For such uses, that driver should work fine off NiMHs in a 6-cell light, too, although that does seem a little on the heavy side.


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## Seiko (Apr 13, 2009)

Benson said:


> or better, AWs IMR26500 (safe chemistry, no protection needed), which should be available any day now.



I totally agree, and once they are available, it would save alot of hassle. I forgot that they were coming out. Editing the main post now to reflect that. Assuming that they will actually be 50mm in height not 65 like the last C size.

Thanks alot for the runtime heat issue! gives me a bit more confidence in letting it run for long periods before I shim it.


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## 737mech (Apr 13, 2009)

Hey Seiko, thanks for this mod post. I ordered stuff to do 2 of these lights with the Mag ring kit. Just need to go pick up a couple 2C hosts now. Did you use a glass lens?


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## Seiko (Apr 13, 2009)

Your welcome. Glad someone can use it 

As far as lens, Ill probably put a uCL or boro from lighthound.com once I trim it down. Adds $10 or so with shipping to the build cost but 10% boost in output over the stock mag lens, so worth it. Good luck on your build If you run into any trouble don't hesitate to ask for help.


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## gswitter (Apr 13, 2009)

Nice build.

I've got a Mag modded with that same reflector (the builder replaced the heat sink and driver), and I'm really impressed with it - so much so that I rarely reach for my 1111/1185/5761 builds anymore.


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## Seiko (Apr 14, 2009)

gswitter said:


> Nice build.
> 
> I've got a Mag modded with that same reflector (the builder replaced the heat sink and driver), and I'm really impressed with it - so much so that I rarely reach for my 1111/1185/5761 builds anymore.



Thanks,
My 5761 mag2c just STOMPS this thing in terms of color and output. However, the P7 will run longer,cooler, and more reliably. So they each have their own uses.


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## LiteFan (Apr 14, 2009)

Going to have a go at building this, never have soldered but looks simple enough. Thanks for the info Seiko. Just ordered the dropin.


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## kicken_bright (May 18, 2009)

Hi! does anyone know if this set-up could be done with two AW protected 17500 cells? Wouldn't those fit nicely into the 2C mag body? Will the P7 draw too much current? Thanks in advance!


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## kavvika (Jun 27, 2009)

Thanks for the tip Seiko. I snagged one of these modules when they went on sale for $20.83 for one day. It arrived this morning and it's now installed in my 2C. It's my first P7 light ever! The output is so impressive, and tint is decent, too. Apparently the circuit is relatively efficient as well. Not that I'd have any right to complain: for how much I paid for the entire completed module, I couldn't even buy a premium P7 emitter alone domestically! Mine is running on 2x unprotected 18650's and I did try two of AW's 17500's, but the runtime is quite short on the smaller cells. I used 22Ga wires to wire up the module to the switch and cut them 1 1/2" long to keep losses to a minimum. I screwed the bezel ring on tight then tightened the head down so the pill would make good contact with the body. I didn't use any heatsinking compound, but it seems the heat makes its way out to the head quickly and the emitter isn't overheating. This is a great way to get started with quad-core emitters on a budget.


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## SmurfTacular (Apr 17, 2010)

Wow what a great tutorial. How bright is that P7? Do you think it is 900 Lumens?


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## csa (Apr 17, 2010)

Great tutorial! Thanks for posting!


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## KurtS (Aug 15, 2011)

I'd like to upgrade a 2C [email protected] (non-C prefix) that I inherited. 
I like this mod but I'd like to run standard batteries and was thinking of running 3x123's. But.... the module is rated at 3.6-8.4V. Looking at the P7 specs, it looks like the module is regulating the LED to 3.6-4.2V.
Should I run 3x123 (~9V) and risk overvoltage (if the 8.4V is to be believed)? Or maybe add a dropping resistor? Or run 2x123 and be at 6V? Any other thoughts/ideas or options?

On a related topic, what's holding the [email protected] switch in place *after* I have loosened the 2 mm set screw in the switch? I backed off the set screw and can feel the switch being a little looser, but even with some firm taps on the brown sleeve, it hasn't budged....

Thanks!
Kurt


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## Stephen Wallace (Aug 15, 2011)

I'll be honest - I don't know if this is the actual answer, as I have always stuck with D cell Mags, and never owned a C. However, with the pre-D serial D cell Mags, the switch has to be removed from the front of the light, and won't go out through the rear. There is a threaded plastic collar, as well as the switch screw, holding the switch in place, preventing the switch from coming out through the front until the collar is removed. 

Like I said, I don't if the old C cells are the same, but might be why you cannot remove the switch.


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## KurtS (Aug 15, 2011)

I can't see how the switch comes out the front unless the aluminum ring is removed and that requires a special spanner wrench. And I don't see what's holding it from going out the rear.  
This should be easy, but I'm missing something.....

The rear arrow points to the brown sleeve part of the switch, btw.


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## Stephen Wallace (Aug 15, 2011)

That does look somewhat like the D cell, only with a metal collar rather than a plastic one. A used a pair of needle nosed pliers to unscrew the collar from my D cell. Again, I cannot say for sure that the C cell version will be threaded in like the D cell version. 

In the D cell, the tube is bored out wider where the switch is than where the batteries are, so the switch butts up against a ledge. It is that that prevents the switch coming out from the rear - quite simply, the switch is too wide to go out through the rear. Removing the retaining collar allows it out through the front. If it is like the old D cell, you have to remove that collar, or the switch isn't coming out.


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## KurtS (Aug 15, 2011)

Thanks Stephen. That was it, there was an internal shoulder that locates it rearward. I assumed the collar was locating it. Expensive design to make with internal machining and threads.

Now, back to the other question, will 123 batteries work with this module?


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## moderator007 (Aug 15, 2011)

It might and it might not. .6v over spec doesnt seem like much. You may have to try it and see and hope it doesnt let the magic smoke out. This driver may work as a reviewer says it only gave 2.8 amps out. Its 22mm in dia and the mag is close to 26mm inside dia. If you can fit it, then you could use 3 li-ion 16340 or 123.


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## KurtS (Aug 18, 2011)

I have not dealt much with circuits that regulate like this.
Will the lumen output be greater if powered by 6 volts vs 9 volts? I'd think that as long it was able to pull 10-12 watts (3.6-4.2 volts @ 2.8 amps) from either setup, it should be the same. 
But can two 123's provide that much current, 2 amps?


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## moderator007 (Aug 18, 2011)

If you used AW LiMN IMR 123a 550mah then it should be able to handle 2 amps. These are rated at 8c. No pcb.
There should not be very much difference between 6v and 9v. Buck circuits usually will vary in efficiency with there input voltage.
123a primary im really not sure. Maybe some one else Knows for sure. This thread may help as it seems he discharged at 2.5 amps.


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## KurtS (Aug 22, 2011)

So I realized there's several different modules from DX you can use for this build.
The P7 module listed above. 
The XM-L module - http://www.dealextreme.com/p/cree-x...-drop-in-module-with-textured-reflector-58481
And a whole bunch of modules with 3 to 6 Cree's chips in each module - http://s.dealextreme.com/search/cree+module+52

The modules vary some in their voltage specs. 
I'm gonna try the XM-L, which also happens to handle up to 12V (so I can use 3x123's). 

007 - I read that you really liked the XM-L with the Rebel reflector. I assume that I could remove the reflector that comes with the DX module if I really wanted and install a Rebel reflector (and thus have a focusable beam). Maybe I won't know that answer til I get the module.

Thanks for the help!


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## moderator007 (Aug 23, 2011)

I dont think the rebel reflector will work with the Dx module reflector setup. You will need a heat sink that goes inside the mag tube in front of the switch to mount the xm-l on to. The rebel reflector is the original led maglite reflector. It has a more tighter hot spot than the incandescent reflector. The focus point in the rebel reflector with the xm-l is about where the bottom of the led is. Not the bottom of the board the led is soldered to. So its possible to have it focused with out mounting the led on a pedestal as i do with my heatsinks and the rebel reflector. I do like the rebel reflector and the xm-l. I built one mag with cree xre r2 and the rebel. Very tight beam of light but the xml will out do it with just shear lumens output.
The 5 cree r2 module reflector at dx has been known to be a very bright drop in for the mag with a little filing work. The xm-l module reflector you linked will probably not be as bright as the 5 cree r2. But the xm-l should have a tighter hot spot. Depends on what you want.


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## KurtS (Aug 23, 2011)

I wanted a little bit more throw than flood, so hopefully I chose right. And let's me run primaries too. I'll let you know when everything gets here and installed. 

Thanks again!


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