SF Z41 tailcap shredding 18650 batteries

[etc]

I wish I had paid more attention to which brands were more vulnerable but I got at least one battery damaged beyond any repair. Well, I suppose I could repair it by soldering something to it. It ground a hole in the negative side. The constant twist-on and twist-off of the Surefire Z41 tailcap. And the 2 cells were protected, in Malkoff MD4 so the tension was higher than in an MD2 with an unprotected 18650.

So Z41 works really with with disposable primaries. Not expensive protected 18650s. I migrated almost completely to Malkoff clickies. Whatever they are called.

 

[thermal guy]

All of malkoff tails will destroy the battery. His springs are sharp. I learned a while ago to change the batteries from the head.

 

[yellow]

When "sharp" spring noticed - get a file/sandpaper and round it up. It just is a tiny burr at the end.
Problem solved

 

[Kestrel]

I concur on deburring the Z41 spring end. Easy to do, which prevents abuse on most of my LiIon cells. I do try to stick with quality 18650's, which should have steel end caps (all my AW's, for example). I have one off-brand 18650 that just has a plated PCB for its Neg terminal; that one is used under a McClicky.