9x 18650 in Mag 3D

The title pretty much covers it.
Is it possible to bore out a 3D mag enough to accept 9 18650 batteries? If you could that would be sweet, but if you can't, oh well. If this is possible then who would I go see? Jesus? If this isn't possible what's my next best option? H22A's new Mammoth?
If I think right, I should be able to get 6 18650's in a 3D without any boring. Right?

Thanks
Spencer

Impossible !
You could get max. 3x17670 in a Mag D-Tube WITH Tribore or 4x 14500 with Quadbore.
So check Elephant 2 by fivemega or the Mammoth

You can get six 18650's in a Mag 3D but it still needs to be bored out.

the 3-wide stack of 18650's is i think bigger around than the outside of the MagD. Best bet would be to do an Elephant or Mammoth as stated above.

Shane

spencer said:

The title pretty much covers it.
Is it possible to bore out a 3D mag enough to accept 9 18650 batteries? If you could that would be sweet, but if you can't, oh well. If this is possible then who would I go see? Jesus? If this isn't possible what's my next best option? H22A's new Mammoth?
If I think right, I should be able to get 6 18650's in a 3D without any boring. Right?

Thanks
Spencer

Click to expand...

A little math reveals the size of the tube containing a triangular battery array:
Battery Tube Diameter= Battery Diameter * [1+(2/(3^0.5))]
(2 Divided by the (Square Root of 3)) Plus 1 equals a Constant of 2.1547
2.1547 * 18mm (18650 diam) = 38.7846mm or 1.527"

A current day MagLite's tube diameter is advertised as 1 9/16" or 1.5625 inch. The one I have measures closer to 1.55", a little smaller. Assuming an OD of 1.5625 gives a wall thickness of 0.018" or 1/56th of an inch. There's not much room left over for threads. So after you epoxy the tailcap on and install a charging jack, tell your friends not to squeeze it. And whatever you do, don't drop it. All kidding aside, 18650's are usually larger than 18 mm. That would mean the circle containing a triangular arrangement of 18650's would likely be larger than the outside diameter of the current MagLites.

I have an old pre-2001 2D cell MagLite. The ones without the D at the beginning of the serial number. They are actually a little bigger. Its outer diameter is 1.64". That leaves you with a wall thickness of 0.056", almost 1/16th". That's if you could find an 18650 that was only 18 mm in diameter. And if you could find someone that wanted to sell an older 4D cell MagLite. And if you could find a machinist willing to work on it for just this one piece, even if you could afford what he'd likely charge.

Well it's a lot going against you, but hang in there. You never know what you can come up with until you try...

Quasi-Proof
If you're wondering where this comes from, the red triangle happens to be a classic 30° 60° 90°. Side "a" on the unit circle would normally be the square root of 3 divided by 2. A.K.A. cosine 30°. Since it would be better in developing a constant if side "a" had a length of 1, multiply all the sides by the reciprocal of the square root of 3 divided by 2. Which explains why it's upside down in the formula. The answer for the length of side "c" (hypotenuse) is 1.154700538. The small segment of the hypotenuse "d" then is 0.154700538. That's relative to a radius of 1. The plus one is for the radius on the other side of the battery's center to the outside of the larger circle. Since nobody says an 18650 has a radius of 9mm, instead of doubling 2.1547, leave it as is and it works with the battery's diameter.

Wow, very detailed. Thank you very much.

spencer said:

Wow, very detailed. Thank you very much.

Click to expand...

Glad to be of help...

What are you trying do exactly? Unless you actually need 33V (9 LiIons in series) there is more than likely a suitable alternative for your 18650s.
Are you trying to drive an incan in a 3s3p configuration, to make a Mag85? Just a random guess.

If so, I'd recommend getting something like the Kaidomain 5Ah D-Cells instead. Total capacity will be only slightly less than 3p 18650s, and price will be a lot cheaper, especially considering modding will not be necessary*

Another option would be to buy 6 AW C-Cells, and a 3C mag. Install one set, carry the other set as spares. Collectively, you'll have the same runtime as you would with 9 18650s. For most hotwires, you won't be able to use your whole runtime continuously anyway, due to heat buildup, so since you'll have to take breaks to let the light cool periodically anyway, switching out cells for spares shoudln't be too much of a hassle.

But please tell us what your specific application is, and we can give specific suggestions, rather than my above guesswork.



*These are known to have a sensitive short circuit protection, and require soft start to light lamps like the Philips 5761, but the 1185 should be low enough current to start without a soft starter. Even so, a soft starter is considerably easier to implement than any sort of machining. Especially if you don't have a lathe sitting around...

I am 100% sure that you cannot fit 3 wide 18650 in a MagD. This is why we started going to the Elephant wide body models. With D Mag boring you can fit NiMH "A" sizes like 2/3A, 4/5A, Full A. Likewise you can fit 3 wide 17670 as in this mod.

I should have said in my last post that you can get six 18650's in a 3D with the cells stacked x2 and possibly removing the switch. You can also open up the tail cap so the cells fit flush.

LuxLuthor said:

I am 100% sure that you cannot fit 3 wide 18650 in a MagD. This is why we started going to the Elephant wide body models. With D Mag boring you can fit NiMH "A" sizes like 2/3A, 4/5A, Full A. Likewise you can fit 3 wide 17670 as in this mod.

Click to expand...

I wonder how he managed to make those battery channels in the wall of the MagLite? Apart from being a recognized master of course. An excellent way to solve the problem of having no threads left for the tail cap.

I was planning on making a multi CREE light with long runtime. I haven't heard good things about KD's D cells and I'm looking for other alternatives. The planned light would have 8 Crees (2 Sharks with 4 LED's a Shark) for maximum brightness so power requirements would be fairly demanding on high.