Do 4 18650 Cells fit into a Mag 4D?

[Der Wichtel]

Hi,
just wanted to know if 4 18650 cells can fit into a Mag 4D with some tailspring moddings.
Since normal D size batteries are 60mm long, 4 18650 will be 2-3cm longer than 4 D's.

 

[Lumencraft (Matt)]

Hey Der Wichtel,

I run 4x sanyo VT cells in a 4D mag 623 with a tail cap mod. There is a little over a 1/2 left in the tail cap for the rubber boot with copper wire for a contact.

 

[Der Wichtel]

Thanks.
Are the Sanyo VT unprotected? because the protection circuit will add 2mm to each sell.
Do you mean 1/2 inch?

 

[Lumencraft (Matt)]

Yes, the sanyo VTs are an unprotected "safe chemistry" type cell from makita tool pack that I added a 1mm magnet to the top of. I don't have 4 protected cells laying around right now, but I put the cells in just now and stuck 8x1mm magnets on the end and with the rubber boot removed they still fit with room to spare. About 6mm in my case.

And ya 1/2 inch was what I meant, You should be able to get your 4 cells in provided you can get creative with the tail mod, I don't think a cut down mag spring would work with 4 protected cells ( I could be wrong), but if you found a smaller spring or used a rubber boot I think it would work. If you do decide to go with a rubber boot though be careful, it the rubber is too stiff the button top/or magnet can mash the bottom of the next cell. You probably already knew this, but I though I would mention just in case.

 

[Der Wichtel]

Ok that sounds good.
=> Mag 4D ordered ^^

Too bad that you can only get black 4Ds here in Germany. But found a red one

I already have an idea. I deanodize the tailcap from the inside. Then I use copper desolder wick as contact with low resistance. After that I will fill it with silicone as "spring".
And maybe I should add a little copper plate.

 

[PCC]

I thought that alkaline/rechargeable D cells were 61.5mm in height and that unprotected 18650s are supposed to be 65mm? Adding the protection circuit should bring the height to about 67mm.

4 X 61.5 = 246mm
4 X 67 = 268mm
268 - 246 = 22mm difference.

The tail cap spring on D-cell MagLites is pretty long so it might work with some modification of the spring or tail cap or both.

 

[Thujone]

Yeah... It may be tight, will end up being a full inch longer than 4 D cells.

 

[spencer]

If you get it bi bored then you can get 4 in a 3D for sure and maybe a 2D.

 

[B30wuLF]

a trustfire 18650 protected is 67.5mm long. so the 4 pack will be 270mm.

i am working on the same problem with a 6D. 5 18650 are 30mm short of the spring but with the "rubber and wire spring" 6 could fit in there.

@ spencer:
tempting idea (12x 18650 in a 6D :huh but to mill inside such a long tube?
@ wichtel:
6x 18650 will be a real challenge for your driver

 

[baexmeyer]

Der Wichtel,

Do you have any picks of your mod. I have come across this dilemma as well.

 

[Der Wichtel]

I'm using somethig like this as the tailcapspring
http://daoriginal.da.funpic.de/data/Dsink/IMG_0717.JPG

 

[737mech]

I am using 4 AW 18650's in my 4D triple P7. I made a battery holder out of PVC and for the tailcap I used my dremel to grind a recess in the center then I used some 5 minute Devcon epoxy to hold a spring from a surefire twist tailcap. Works pretty good.

 

[baexmeyer]

737,

That is what I was planning on doing. Removing the anno and trying to mount a spring to the tail. Thanks.

DW,

You mod seems extremely easy I will more than likely try your mod first before something more permanent.

 

[TallNHairyDave]

D'oh! Just noticed the age of the original post in this thread :laughing:

I'll move my reply to a thread of it's own because I started rambling about my current build which will use 4 x 18650 in a 4D mag.