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Risks of salvaged 18650 from laptop batteries
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Dhanushka:
Dear all,
 
I brought a laptop battery to salvage few 18650 batteries. This battery pack was a cheap replaceable one and this was not used by anyone. But when I open it carefully there was a nasty tight smell inside but there was not ant leaked liquid. However I did not care about that. But the spot welded places have corroded of 4 batteries. Only two cells could be salvaged. These two cells has no any nasty smell or corroded places but other 4 had. All batteries were at about 0 V. I recharged the good two batteries with TP4056 module and that was bit successful as I think because that charged up to 4.2V and current through a 0.47 ohm (printed value) resistor was 5 amps. But the voltage drops about 0.010 V per day.

My main questions are,

1. Is the self discharging of this cells normal?
2. Are these batteries safe to use?
3. The nasty smell can make a health problem?

Thanks
sleemanj:

  Any with corrosion of course throw away

  0v, some will say throw away, I will say OK, IF they hold charge AND you charge safely (don't charge somewhere that fire would be damaging)

  5A discharge is way too much for salvaged laptop cells though, I'd be surprised if that is even in their new specification a 5A discharge on a typical laptop cell would be less than half an hour battery life, they are not designed for that, keep discharge to 1A (and charge).

  0.01V initial self discharge from the 4.2v top-of-charge would be OK, but it should level out, if it keeps discharging such that it goes below 4v from a 4.2v charge, that cell would be questionable

  The smell, well, don't go huffing it, but I doubt it's particularly harmful for an occasional exposure, bigclive has opened lots of cells and he's still alive.
kripton2035:
lithium vapors are toxic at high dose. manipulate them in a well ventilated area it should be ok. in pro shops for batteries, you need a very powerful hvac for these.
Rick Law:

--- Quote from: Dhanushka on August 19, 2019, 09:52:31 am ---...
 I recharged the good two batteries with TP4056 module and that was bit successful as I think because that charged up to 4.2V and current through a 0.47 ohm (printed value) resistor was 5 amps. But the voltage drops about 0.010 V per day.
...

--- End quote ---

Since you are testing it at such high amp, are you planning on vaping with it?

Even with "new" batteries, horror story is plentiful when placed so close to face and body with vaping.  I don't do that kind of vaping, but if I do, I would only use best battery money can buy.  Those big multi-18650 types seem to sacrifice all other aspects (including safety) in order to get very high-amps; particularly with some of the mods they sell - all to draw even higher Amp.   I am sure thousands are using that every day, but I also am sure that there are "once in a life time experiences" that one rather not to have...

I do use e-cig, but for safety, I use one designed to use a small 200mAH battery.  Too small to blow up big time so damage is limited.

As said, plenty of horror stories, here is one for example and he is using a new battery:
Example from UK:  https://www.dailymail.co.uk/news/article-7340519/Driver-engulfed-flames-left-degree-burns-vape-EXPLODED.html 
KL27x:

--- Quote ---1. Is the self discharging of this cells normal?
--- End quote ---
Not normal for a good cell. A good cell charged to 4.20 can retain that for one the order of a year, maybe several, before dropping to 4.19V.

An older cell might drop at first but stop at some point. Maybe 4.15ish.


--- Quote ---2. Are these batteries safe to use?
--- End quote ---
Depends on what you use it for, and what is your definition of safe. They're definitely damaged, because they were 0V when you started. And you fast charged them from that state. They're obviously damaged goods, but again. It depends on what you wanna do with them. A cell venting hot gas and flame might be no big deal. For low current, low charge stuff, in particular, it might actually work ok, for that; I suspect your cells have a high internal resistance and won't be very good at high discharge application; they might have very short life and get hot. But that's for you to find out.


--- Quote ---3. The nasty smell can make a health problem?
--- End quote ---
:-//
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