Z41 tailcap wearing out the bottom of protected 18650's.

etc

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I have at least one battery that became unusable after the Z41 wore the plating off the protected cells bottom. It looked like cheap plating. I've never had that issue with the non-protected authentic 3500 mah "GA".

The trend seems to be the protected 18650 is considerably longer exerting more pressure on the Z41 tailcap. The longer protected cells work well with Malkoff clickies.
 

etc

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Here is an example of what I am talking about. This is the worst one but some others are also getting there. Base unprotected 3500 mAh "GA" cells seem to be the best, it's the aftermarket added protection that seems to make it more vulnerable. Either due to increased length or due to the inferior material used.

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Kestrel

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I've always been a little surprised that more folks haven't had these complaints; even back when all my LiIon cells were AW (with a good steel cap on the 'neg', covering the protection circuit), I always took a tiny file or dremel bit and smoothed over the burr at the end of my Z41 springs.

In the old days of CR123 primaries; sure, it didn't hurt much to scrape a fresh surface for good electrical contact. But in recent years I've seen simple circuit board plating used as the 'neg' surface for LiIons, and these certainly will wear far faster, to eventual failure of the surface to serve as an electrical contact.

I have been pleased overall with all of my 'smoothed' Z41 spring ends however; I have gotten exceptional lifetimes from my LiIon cells, and certainly wouldn't want to have to retire any of them earlier due to spring damage of the 'neg' plate.
 
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etc

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That's a good idea. I think I have at least one offending Z41, the others don't seem as bad but will check them out.
 
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