Is this 18650 safe to use? Slightly peeled wrapping

kofkop

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Hi all,

I'm fairly new to 18650-based flashlights and recently purchased a used SC600w mk III HI, which I am still waiting for to arrive in the mail. In this regard I also purchased a couple LG MJ1s as the protected 18650s I already have don't fit that particular flashlight. The zip-lock bag the cells were contained within had probably not been properly closed before they were packaged, so upon opening it one of the cells slid out onto the floor, not hard at all, but enough to create a couple of small peels in the wrapping. As I didn't have a chance to look over the cells before one of them slid out I guess it could technically already have had peeling wrapping, although I doubt it.

I am aware of the potential dangers of 18650s and don't want to take any unnecessary risks, but I couldn't really find any conclusive answer online as to whether this would be enough damage to warrant a rewrapping. I attempted to use a hair dryer to get the peeling parts to stick but it didn't suffice.

Any advice is appreciated.

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KITROBASKIN

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Illumination has battery wrappers and their shipping costs are fair. You might get by but you could end up with a shortness not worth it.
 

PhotonWrangler

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If the cells aren't bulging, I don't think it a major issue, however I would probably paint a dab of non-metallic nail polish on the top where the wrapping is damaged.
 

Gauss163

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The exposed metal on the top of the cell greatly increases the chance of a short because - unlike other common consumer level cells - the entire can is negative for 18650 cells. So it takes only a very short piece of metal (keys, coins) to connect the damage-exposed negative top edge to the positive button-top - yielding a dangerous short circuit.

So it would be wise to patch the top tear asap.
 
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Thetasigma

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With no physical damage to the cell, just acquire some 18650 wraps from your preferred dealer (I like Illumn), grab a hair dryer/heat gun and rewrap this cell. Wouldn't recommend using it in the meantime since as mentioned, the whole can of Li-Ion rechargeables are negative and can be easily shorted or stuck on if in a light
 

Timothybil

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You guys correct my thinking on this if needed: I would get some clear wraps and re-wrap the cell. But since we are dealing with a flat top, I would first carefully trim the current wrapper right below the top of the cell, so that there is only a single layer of wrapper on the top of the cell. Of course I am only recommending this course if you want to maintain the cell identity as it's printed on the current wrapper. If you don't care, or just want to write the info an the new wrapper, then re-wrap the cell. There is a lot of energy in a small package there, and it definitely wouldn't do to let the large billows of magic smoke out.
 

hiuintahs

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Take the entire green wrapper off and re-wrap. You can get 18650 heat shrinks cheaply on Ebay. You'll lose the marking and labeling but you'll always remember what battery it was. At least you'll have a good usable battery.
 

Woods Walker

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I fixed a 16650 using black electrical tape with kinda the same issue. That said it's really really easy to shrink wrap a new cover. Costs nearly nothing.

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fivemega

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Since cost of good 18650 is pretty low these days, I wouldn't bother to repair and reuse damaged old cell which may cause problem and make me nervous every time I use it.
Value you life little more than that.
 

WalkIntoTheLight

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If the cells aren't bulging, I don't think it a major issue, however I would probably paint a dab of non-metallic nail polish on the top where the wrapping is damaged.
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that is a really good idea. I have an identical situation

Problem is, it might just crack or the tear in the wrap might get bigger, etc.

Just buy some wraps and re-wrap it. You can get enough wraps for 10 lights for about $1 off Ebay. Buy them even if you don't need them now, because someday you will.
 

Gauss163

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I wouldn't trust nail polish, e.g. with thermal changes it may expand and contract at rates different than the can so eventually crack and/or lose adhesion. A quick web search didn't turn up much on that, other than one guy who used green nail polish as a solder mask (see photo below). Better to buy some battery heat-shrink wrap and follow the rewrapping tutorial thread above. It's very cheap and widely available so there's really no excuse to use half-baked solutions that might prove dangerous.

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