need advice on 2D to 2 x 18650 tail cap spring

How are you all modifying your tail cap spring or what parts are you using to accommodate 2 18650's in a 2 D mag. I have the sleeves to fit, just need a good means to fit the batteries. I have a golden shorty mad spring but it will shred the wrapping on my batteries and it's real tight.

I'm using foam wrapped with copper ( desoldering wick)

You can turn the spring over so the top sticks into the tail cap, then recoil the bottom of the spring so it will make contact with end of the 18650 cell. Bending the D tail cap spring is easier said than done but it works in a pinch.

Kelly

I ripped out a (wimpier) spring from an El Cheapo 2D, and cut & bent it to fit the mag tailcap.

What I would suggest (and what I did) is the following:

Take the spring, and cut all of the coil off except for the base (and the remaining coil of wire that is meant to retain the spare bulb). You might want to leave a little coil in place in order to make sure that the spring will be able to stay in the tailcap by itself.

Then, take a vice and use it to make the small bulb retaining coil smaller. there isn't really a specific way to do this; I just put the coil perpendicular to the vice and used it to squeeze the sides of the coil until the end was centered in the middle of the coil. Then, you need to make this coil stick out so it functions as a spring. I would suggest using something as a lever, or putting it in the edge of the vice at an angle.

The new end of the spring should stick out about 7-8 mm from the bottom of the coil.

Here is what mine looks like:




I am currently using it with IMR 26650s, but I was previously using it with both protected and unprotected 18650s.

Thanks for all the suggestions.

Is it possible to solder a steel spring and washer together? I found some parts at Ace Hardware that will work, but not sure how they will solder together. Plus they may have some added resistance. Not sure, still playing around with it.

Has anyone ever tried to drop the spring from a C Mag into the de-anodized tailcap of a D Mag? I don't have a C spring to try, but it seems like it would just fit diameter-wise. Would the tension on the 18650s be acceptable with this set-up?

Howecollc said:

Has anyone ever tried to drop the spring from a C Mag into the de-anodized tailcap of a D Mag? I don't have a C spring to try, but it seems like it would just fit diameter-wise. Would the tension on the 18650s be acceptable with this set-up?

Click to expand...

M*g "C" spring is too small (diameter-wise and length) for "D" size cap when using 2x18650
3 IMR18500 will fit in 2D with tail cap deanodize and braid of copper wire instead of spring.

Finally getting around to posting my solution. Think it will work fine. Sorry about the bad cell phone pick, but I think its sufficient.



Went to Ace and purchased a washer and steel spring JB welded it together after unsuccessfully trying to solder it together and used a piece of copper desoldering braid to complete the connection. Almost a perfect fit.



Here it is inside the tailcap. When screwed in the spring compressed and holds the copper braid securely. Tail cap is only just shy of being completely closed. Wish I had a lathe?

how tall a spring do you need?

With the ultrafire bats I tested with only a few mm. The spring compresses almost all the way down.