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Leaving out Lithium Ion Batteries

julianthedragon

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How safe is it (for battery health or in general) to leave lithium batteries out for a long time without discharging and charging them regularly?

For instance let's say I have a laser I rarely use that takes a 26650 batt. It's fully charged but since I only use the laser on occassion it can last months on one charge. Is there no harm in this or should I be giving it a workout more often?

From what I know about li-ion batteries, 1) they will gradually drain over time in storage and 2) it is healthier to give them partial charge/discharge cycles than fully drain and fully charge, so I'm asking with that in mind
 



gazer101

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Afaik leaving batteries at a stable charge should offer similar proportional degredation to had you been using them in that time.

The trick is to store them at their nominal storage voltage (3.7V per cell for a lithium ion/polymer battery).

Also best to keep them separate from the laser in case the internal circuitry had a pull up resistor or something that could drain the battery to 0 over a few months or something
 

Giannis_TDM

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Afaik leaving batteries at a stable charge should offer similar proportional degredation to had you been using them in that time.

The trick is to store them at their nominal storage voltage (3.7V per cell for a lithium ion/polymer battery).

Also best to keep them separate from the laser in case the internal circuitry had a pull up resistor or something that could drain the battery to 0 over a few months or something
That is not correct, proper storage voltage is 3.815v, which is also what is used for, for example, drone batteries when shipped for sale since they will most likely sell in a month or two since they leave the factory and the shop can't be expected to maintain every battery so manufacturers have worked out that that's the best voltage for long term storage in terms of preserving them.

EDIT also do what gazer suggested, the quiescent current of any driver, although in the 100s uA range for most quality drivers WILL drain the battery over time, have lost a lot of good cells due to that, not on lasers mind you but a quiescent current will present on any electronic device due to the sheer fact that we can't cheat physics, even glass has a quiescent current/leakage current/insulation resistance but you better start counting the decimals :p
 

Giannis_TDM

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Apparently you can store the batteries anything above 2.5v because they start to decompose. https://batterybro.com/blogs/18650-.../77975750-how-to-store-18650-batteries-safely
Very misleading cause if any lion or lipo battery is discharged below 3v it will start to deteriorate rapidly 2.5 is where it has reached a state which deems it unrecoverable, as said optimal voltage is 3.815v and that's coming from multiple sources and literally any lipo battery manufacturer since lipos became a thing.
 

Unown (WILD)

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Very misleading cause if any lion or lipo battery is discharged below 3v it will start to deteriorate rapidly 2.5 is where it has reached a state which deems it unrecoverable, as said optimal voltage is 3.815v and that's coming from multiple sources and literally any lipo battery manufacturer since lipos became a thing.
Actually no it can be recovered even bellow 1 volt. Not always but it can still be recovered with reduced capacity. I've revived batteries that low before myself. I know you like to be right all the time but I stand with the info I posted
 

Giannis_TDM

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Actually no it can be recovered even bellow 1 volt. Not always but it can still be recovered with reduced capacity. I've revived batteries that low before myself. I know you like to be right all the time but I stand with the info I posted
Exactly, the battery will never recover to a normal state and on that might I add that if it "recovers" as you like to say from 1v, self discharge is gonna be a few magnitudes more than stock along with internal resistance, on that also, depending on how bad it is, it may also refuse to charge back to 4.2v hence why it is more than commonly accepted that any cell below 3v is better recycled. Sorry but I can't call the delusion of you just bumping up the voltage from AAA levels to 4v a recovery, and what I said is backed by my own expirience while"re-covering" both lipos and lions and a multitude of sources steming from EEs I know to articles and papers.Thanks for backing me up bud!
 

gazer101

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That is not correct, proper storage voltage is 3.815v, which is also what is used for, for example, drone batteries when shipped for sale since they will most likely sell in a month or two since they leave the factory and the shop can't be expected to maintain every battery so manufacturers have worked out that that's the best voltage for long term storage in terms of preserving them.

EDIT also do what gazer suggested, the quiescent current of any driver, although in the 100s uA range for most quality drivers WILL drain the battery over time, have lost a lot of good cells due to that, not on lasers mind you but a quiescent current will present on any electronic device due to the sheer fact that we can't cheat physics, even glass has a quiescent current/leakage current/insulation resistance but you better start counting the decimals :p
Most of my drone batteries ship at 3.75V, just curious how did they arrived at that 3.815V figure?
 

Giannis_TDM

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Most of my drone batteries ship at 3.75V, just curious how did they arrived at that 3.815V figure?
Every one I have purchased was 3.815v, I asked the shop and they told me so too, can also recall the documentation in my batterie's manual saying so, If you are saying how they arrived at that, research and experimenting.
 

Unown (WILD)

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Exactly, the battery will never recover to a normal state and on that might I add that if it "recovers" as you like to say from 1v, self discharge is gonna be a few magnitudes more than stock along with internal resistance, on that also, depending on how bad it is, it may also refuse to charge back to 4.2v hence why it is more than commonly accepted that any cell below 3v is better recycled. Sorry but I can't call the delusion of you just bumping up the voltage from AAA levels to 4v a recovery, and what I said is backed by my own expirience while"re-covering" both lipos and lions and a multitude of sources steming from EEs I know to articles and papers.Thanks for backing me up bud!
It's not a delusion. The recovered cells are still useful and many people I'm sure can't be all disillusioned.
 

Unown (WILD)

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Yes but on a chemical level the damage is done and risk of future failure is greatly increased
So? Reduced capacity is still useful. Not sure what failure you're talking about. The cells will just not hold a charge as much as a newer cell. I wouldn't use them in battery packs but things like flashlights or lower end devices can still make use for them. I got a flashlight that uses 4 18650s and I use older cells with it. Works just fine.
 




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