2C Mag Mod (Lots of pics)

Hiya Folks,

I came home to a wonderful surprise last night of Chicken Marsala...and a big padded Manila envelope! After reading ezeqdb's excellent results with his 3D mag mod, I decided I wanted to give it a shot with a 2C (I love this form factor). Again, thanks Ezeqdb for the idea and guidence.

Even though I have a bunch of 18650's, I wanted to maximize the runtime, so I ordered some protected 25500's (5500ma rating...we'll see...).

Here's a shot of the new drop-in, host, and batteries:

After a complete tear down of the mag, I noticed I'll need to do a lot more grinding than if it were a D mag head:

If you notice around the inside edge, that was my subtle attempt at using a dremel tool. It didn't work too well. I can't grind the drop-in, because I'd end up removing too much metal too close to the driver and emitters, so the head it has to be. I finally gave up at this point and waited till I got to work in the morning.

Today: I'm fortunate enough to have access to a well equip'd machine shop here at work, so it's off to the lathe I go. In all honesty, it took longer for me to remember how to set up the lathe than it did to make the cut (it's been 10yrs). Here's the end result:

The convenient thing about this was that I was able to contour the cut to match the bevel on the drop-in for extra heatsinking.

The next part was modifying the switch. Here I didn't bother to try and use the spring/plunger post assembly and removed it entirely. I soldered on a 16ga wire to the positive exit post of the switch. I don't have to worry about using the negative strip from the bottom of the switch because the head is well grounded now. In fact, I removed that part.

Last thing to do is screw it together and drop in the freshly charged 25500's. What could go wrong?

Ugh... Apparently the protected cells are just that much longer than regular "C"'s that the tail cap will not go on. After a cup of coffee or three I came up with a work-around. :

I used an aluminum ring with a flat spring soldered across it for contact. It screws nicely into the base and holds the cells tight. It also affords me a heck of a failsafe in case one (or both) cells decide to go supernova. The downsides to this are there is no weather protection, and it looks like a hack job... I'll have to think more on this.

Here's the finished product (low mode):

It is disturbingly bright with good throw. I'll try and grab some beamshots tonight when I get home. I'll also enlarge the pictures some when I'm able to get to a real computer. (done) Hope y'all enjoyed it, and if anyone has any suggestions for the tail cap, I'm all ears. Total cost: $33.65 (sans batteries, since 18650's would work fine).


With access to a machine shop, I'd machine off all the anodising (and enough metal till the cells fit) from the inside of the tailcap, toss the spring and put in whatever was needed by way of heavy gauge copper wire till it worked.

Don, I wish that were an option....but the cell diameter is dangerously close to the bottom of the thread grooves. If I milled that away there'd be nothing left to screw in. If I'd stuck to 18650's it would be easy peasy...

Darn....well I guess no one likes re-runs...

Nice! the 2C is the best maglite to do this, I just find my 3D host "full of air" when using just 2x18650

The only bad point of this mod, is that you just can't upgrade it, you need thousands of bucks to increase a few lumens.

BTW, where did you get those 25500? how much real mAh do they have?

I got them from DX sku.26799 . General consensus is that the mah rating is closer to 3500, but still much better than any of the 18650's I have. I still need to do a run down test. Btw, how many amps at the tail are you pulling? I'm getting 1.8-1.9a.


I use a multimeter with short and thick cables and i get 2,5 A (@8 to 8,4V).

I am going to do this exact build :slight_smile:

I have a list on CPF with 10 ways to run 8.4V in Mag 2C.
2 of the ways will allow 2xDX protected C lion to keep the tail on.

thanks ma sha! im going with the dx 25500s since theyre cheap and seem to have slightly higher run times than a 2x 3100 18650

edit: where to get the aw cell extender?

edit edit: just went with a fm cap since hes doing a 30% off run :slight_smile: only ~17 shipped, bringing the total cost to me to about $63

my host was free with amazon reward points lol

Any thoughts about boring out the head since i do not hav access to a lathe? I have a drill. That about it lol

i was able to make that cut using a proxxon rotary tool (ib/e 38481 model#) took me about an hour of grinding and 2 or 3 grinding wheels but now the dropin fits snug

just have to solder it up and maybe get a few gitd o rings to put around the top as the cap does not screw down quite all the way

good build!