SF Z41 tailcap shredding 18650 batteries

etc

Flashlight Enthusiast
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Dec 19, 2004
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5,777
Location
Northern Virginia
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.
 

yellow

Flashlight Enthusiast
Joined
Oct 31, 2002
Messages
4,649
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Baden.at
When "sharp" spring noticed - get a file/sandpaper and round it up. It just is a tiny burr at the end.
Problem solved
 

Kestrel

Flashaholic
Joined
Oct 31, 2007
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7,372
Location
Willamette Valley, OR
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.
 
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