18650 fully discharged in storage and recharged to 3.8v before learning that...

LEDBE
How could that be then if I just pulled 200 18650 from dead laptop pack 0v and charged them at around 300mah then stepped it up after 3v to 800mah .The batteries after doing a discharge test 99% came back over 1000mah .
 
If that was a protected battery, it was sitting all this time with 2.8v, and all this talk is about nothing (although of great educational value).
 
"If" that was a protected battery, "If" the protection circuit worked properly", "If" the battery did not continue to loose voltage while left in a drawer and "If" a person was willing to "assume" that this is what happened (because, they don't actually know) and "If" that person was willing to risk the loss of their property based on such assumptions, over a sub $20 battery, then yes, by all means... it could have been "talk about nothing" or perhaps tomorrows news, and nobody could possibly know which it would be.

Many are willing to risk everything on something as trivial as a sub $20 battery that *may or may not* have been compromised. It is these very people who will cry foul and claim it was someone else's fault, when things don't work out the way they thought it would.

Everyone is free to take however much risk they wish, but *I* feel it is important that everyone be aware of just what kind of risk they are taking, so they can make an educated decision. Assuming something is safe is not the same as knowing. Just read the section on this forum on batteries and safety.

Regards

Christian
 
Even protection circuit is never perfect, nor leak-free; most MOSFETs used to channel up to 20 Amps of current usually have medium to high Rds_on (resistance between Source and Drain of the transistor when it is switched on), and that gradually contributes to parasitic drain (in the order of several microamps or so due to transistor leakage), and it's rare to find the BMS boards with very low Rds_on MOSFETs and/or IGBTs, as they cost twice as much as crappy ones, even though it's a requirement for most CPU voltage regulator(s) to implement the MOSFET with lower Rds_on, especially those in smartphones which the battery life are the biggest factor.

Again, like kaptain_zero said, it's actually your decision what to do with the battery. Choose wisely, though.
 
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kaptain_zero said:
"If" that was a protected battery, "If" the protection circuit worked properly", "If" the battery did not continue to loose voltage while left in a drawer and "If" a person was willing to "assume" that this is what happened (because, they don't actually know) and "If" that person was willing to risk the loss of their property based on such assumptions, over a sub $20 battery, then yes, by all means... it could have been "talk about nothing" or perhaps tomorrows news, and nobody could possibly know which it would be.
Click to expand...

Whether a particular battery is protected or not, is fairly easy to find out in most cases (especially if it's a brand battery), there is no need to assume anything. As for the rest of your insinuations, the laws of physics themselves are probabilistic in nature - brand new cell from major manufacturer can vent the very first time you try to charge it, it's just a question of probabilities.
 
Yep, good answer. Brand new quality cell may vent the first time you try to juice it up, still possible although very unlikely. On unrelated note, Sony have suffered the similar disaster ten years ago, and ended up losing crapload of money recalling the defective cells - it was due to the metal shaving somehow making its way into the cells, making for the recipe of disaster.
 
jn2 said:
[...] at this price point I can't help but think there is something wrong or incomplete with a technology [Li-ion cells] that is so temperamental and sensitive. In addition, all batteries should have a warning on the battery that says exactly "never let charge drop below 3.5 volts, and discard if this happens".
Click to expand...

There is no such warning on Li-ion cells because they are not meant to be sold directly to consumers. For example, see the cease-and-desist letter below that Sony recently sent to a vaping store.

----------

It has come to our attention that you are offering, or have in the past offered, lithium-ion
rechargeable battery cells, purportedly manufactured or supplied by Sony, for sale or
use with e-cigarettes, vaporizer pens or other such products. Bona fide battery cells
that are manufactured by Sony are at all times commonly designated or known as Sony
"VTC" battery cells. These battery cells were made only to be used in connection with
the assembly of battery packs of products such as power tools, which have the
necessary enclosure, protective devices and circuitry that enable safe usage of these
battery cells. Sony lithium-ion rechargeable battery cells (induding those with "VTC"
designation) are not intended for use without such packaging or circuitry, and should not
be used as a standalone product for instance with e-cigarettes, vaporizer pens or other
products of any type.

The use of any Sony lithium ion rechargeable battery cells as a stand-alone
product, including with e-cigarettes, vaporizer pens or other products,
constitutes a DANGEROUS misuse of the battery cells that poses a SERIOUS
RISK of personal injury or property damage. This matter is significant enough that
the U.S. Fire Administration, an arm of the U.S. Department of Homeland Security's
Federal Emergency Management Agency, released a report
https://www.usfa.fema.gov/downloads/...cigarettes.pdf in
October 2014 warning against the dangers involved with improper battery cell use,
storage and charging of battery cells in e-cigarettes. See also a recent statement from
the Consumer Technology Association on lithium ion battery safety available at
http://www.ce.org/Consumer-Info/Battery-Safety.aspx Accordingly, if you are currently
selling or distributing stand-alone Sony lithium-ion rechargeable battery cells, other than
in the condition and for the purpose originally intended by Sony, you must immediately
cease doing so. Sony believes that you should also immediately notify any person to
whom you have sold or supplied any stand-alone Sony titbium-ion rechargeable battery
cells of the danger associated with the misuse of such battery cells and instruct them to
immediately cease using and return the cells to you.

Please contact Sony's consumer product safety office at [email protected] should you
have any questions or concerns.

Very truly yours.


Julio Posse
Director of Product Safety
Sony Electronics Inc.
16535 Via Esprillo, San Diego CA 92127
 
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Apparently, Panasonic 18650 cells do have warning on it. However, I agree it's not really meant to be used in bare configuration by general public. I have used it as such in my flashlight (and handheld diode lasers) without problems - the drivers' low voltage shutdown is rarely used unless I use Lithium : Iron Phosphate cell.
 
Like the usual warning not to short-circuit, nor toss it in fire and that the cell must be charged under special circumstances (ie. proper battery charger).

At least it was also on older Panasonic cells (pink 1,400 mAh 18650) the last time I saw them.
 
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It would SEEM. . . . that flashlight makers that make flashlights that use high amp/ high amp draw/ batteries, install a venting port/ blow out port/ blow out rubber port in the battery compartment. . . . . so that, over time, or with a faulty cell or low voltage or battery failure,
that IF the battery starts to vent, smoke, or explode the rubber port melts or Blows out so that the battery chamber does NOT become a miniature pipe bomb. (Water heaters use a similar process if the water gets to hot or the pressure inside the tank is too great, there is an emergency port/ drainage port/ to release the pressure.)
 
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Also did the same thing to NiMH batteries and they came back to life .I don't know what that thread has to do with anything though
 
NiMH batteries and Lithium-ion batteries both altogether are fundamentally different, BTW. You may get away with charging NiMH battery that's quite dead, but not so much for Lithium-ion batteries. You can charge a dead Li-ion battery a few time, but then there's absolutely no guarantees that it won't go out with a bang.

On the other hand, they're pretty similar as the only electromechanism for production of electricity is movement of ion. In NiMH battery's case, it's Hydrogen, or Potassium (will have to get my hands on industrial chemical book soon), while in Lithium-ion battery's case, it's Lithium. They move towards opposite charge on the electrode (recharging cycle), and back when in use.
 
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Here's an example of what zero volt lithium rechargeables do in real life. I recovered an 18650 from a battery pack that had shorted electronics due to water damage. It charged very slowly to 4.2 volts. I ran it on the Opus analyzer, and it took several cycles to finish. It was charging warmer than usual, and showed higher capacity (false reading). When I came back later, it was 4.08 volts and dropping while showing "Full." Not quite as bad as the other zero volt cell that was hot and showing 3.68 volts when I took it out after it said "Full"...
 
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