Question Doubts about battery storage.

[cloudff7ps1]

What is the best long-term storage voltage for Li-Ion and Li-Po batteries? removable smartphone batteries i have chinese Nokia BP-5L and Xiaomi BM20 do you have any studies that prove the best voltage or voltage range for long term storage?

 

[Ralston18]

By "best long-term storage voltage" do you mean that the batteries are going to be installed in some device (charger ?) other than a smart phone and then stored in some manner?

More information needed.

Nokia BP-5L and Xiaomi BM20

Contact the manufacturers regarding long-term storage requirements.

 

[BFG-9000]

For standard Lithium manganese oxide cells, anywhere between 30% (3.7v) and 50% (3.94v) is fine and 40% (3.82v) probably ideal. Given that the protection circuitry itself draws a small amount of current and if you ever want to use the battery it will be quicker to charge up, I expect for most people 50% would be better, but frequent checking at 40% should yield longest storage life--after 1 year 96% of the capacity should be retained, vs 80% if kept charged to 100% at 25°C

Li-ion batteries are only shipped at 30% for safety reasons, and this leads to a lot of old-stock products having the battery die in the unopened box from self-discharge. That's not just because draining below 2.5v is just as bad for longevity as charging above 4.3v, but because the protection circuits are often set to not allow charging a too-low Li-ion at all to prevent fires.

 

[cloudff7ps1]

my BP-5L and BM20 batteries are not stored inside any device here in my city the temperature varies 33-35C for these conditions of mine what is the best long term storage voltage? Is there any official study on this?

what is the charging frequency and when the voltage drops what voltage is prompt to recharge
?

 

[BFG-9000]

In the link I left for you it explains that at 40°C the permanent capacity loss is typically 15% after a year at 3.82v and 35% at 4.20v. I would suggest you keep your unused cells in the freezer because at 0°C there is only 2% permanent loss per year at 3.82v so it would take 11 years to drop to 80% capacity. Even fully charged to 4.20v there is only 6% loss per year at 0°C

There will be no undervoltage damage to the cells if you catch them before they drop below 3.0v and charge them back up to your desired storage voltage then. How long it takes to drain to there depends on your batteries. The internal self-discharge of Li-ion is pretty low under 4.0v but the protection circuits can cause a small but constant drain until they disconnect, usually ~2.5v.

 

[cloudff7ps1]

I can't freeze I keep it in boxes but I need guidance on which voltage is best for long storage in my 33-35c conditions on these battery models I don't know if bm20 and bp-5l is lipo or liion

I didn't find studies

 

[USAFRet]

long term storage

As has been asked in your storage threads, define "long term".

6 months, 6 years, other?

Batteries are sort of consumables. No matter what you do, they WILL need replacement.

 

[cloudff7ps1]

I have these batteries in reserve to use them in the future but I don't have a set time for when I'm going to use them so I want to preserve them as much as possible so in my conditions I need to find the best voltage to store them

 

[cloudff7ps1]

my BM20 and BP-5L batteries charged at 3.75v to 3.8v is a good margin for long term storage in my 33-35C temperature conditions?

 

[ex_bubblehead]

You're talking no more than 3-5 years life for either type. Even less when abused or left sitting on a shelf without proper attention. As said above, batteries are consumables, you buy a new one when needed.

 

[cloudff7ps1]

3.75v to 3.8v is a good margin for long term storage in my 33-35C temperature conditions?

 

[ex_bubblehead]

3.75v to 3.8v is a good margin for long term storage in my 33-35C temperature conditions?

Not even close. Drop those temperatures by 50% minimum. But, as you've already been told these batteries will age out in only a couple of years whether or not you use them.

 

[cloudff7ps1]

I can't reduce these temperatures I don't use air conditioning very difficult for me to keep these batteries I live in a tropical region and the ambient temperature is this

but referring only to the voltage I showed 3.75v-3.8v are these voltages good for storage?

 

[ex_bubblehead]

I can't reduce these temperatures I don't use air conditioning very difficult for me to keep these batteries I live in a tropical region and the ambient temperature is this

but referring only to the voltage I showed 3.75v-3.8v are these voltages good for storage?

There's FAR more to this than just voltage. Your ambient temperatures will significantly shorten the life of any batteries. Your environment is not conducive to storage of batteries of any kind.

 

[cloudff7ps1]

complicated i don't know what to do my batteries will die prematurely because of the temperature where i live

 

[USAFRet]

complicated i don't know what to do my batteries will die prematurely because of the temperature where i live

Not complicated.

Obtain new batteries when you need them.

 

[cloudff7ps1]

these batteries are hard to get because they are old and my device was designed only for these battery models my intention was to keep these in reserve

 

[DSzymborski]

these batteries are hard to get because they are old and my device was designed only for these battery models my intention was to keep these in reserve

If you must store batteries long-term, then you need to be able to have as optimal conditions as possible for conserving those batteries. The basics of chemistry don't change based on what's convenient for you.

 

[cloudff7ps1]

what are the ideal conditions? under ideal conditions the battery does not die?

 

[Karadjgne]

In a box, in a closet, away from any heat sources. But it's really a moot point as you'll most likely not be worried about those batteries in 3-5 years time, when the current batteries finally quit charging, as you'll most likely have a different phone by then in order to keep up with memory requirements, OS requirements, gimmicks, busted screens etc.

It's why most smart phones don't bother with user serviceable batteries any more, or make battery replacement semi-redundant, it's called planned obsolescence.

 

[DSzymborski]

what are the ideal conditions? under ideal conditions the battery does not die?

Ideal conditions means being stored in cool, dry conditions.

That doesn't mean they won't die; they will. They just won't die as quickly as in your conditions.

You need a new plan as your current one is absolutely terrible and flushing money down the toilet.

 

[TerryLaze]

these batteries are hard to get because they are old and my device was designed only for these battery models my intention was to keep these in reserve

E-bay/ali is full of these batteries, it might be expensive for you due to shipping but they are not hard to find.
Local second hand shops,papers, flea markets, and so on will get you cheaper alternatives.

Also you only need the cases you already have, inside there is a charging circuit that you need to keep and a generic battery that you can change out for a new one.
(By you I mean a professional that knows what they are doing)

 

[cloudff7ps1]

is there any small box sold on aliexpress to keep a temperature lower than room temperature and conserve batteries?

 

[ex_bubblehead]

is there any small box sold on aliexpress to keep a temperature lower than room temperature and conserve batteries?

Yes, it's called a refrigerator. And the types of batteries you're talking about will die a very quick death there. Used or stored 3-5 years is all you get, even if kept in a perfect environment and constant maintenance.

 

[DSzymborski]

is there any small box sold on aliexpress to keep a temperature lower than room temperature and conserve batteries?

That's called an air conditioner.

(Edit: Or a refrigerator. Cooling things significantly below ambient requires a lot of power)

I'm sorry, but this whole plan is a very poorly thought-out one. Basically, you want magic to exist.

Now, you could spend thousands of dollars on ideal conditions for hoarding batteries for ancient technology, but in this case, it would be far cheaper to just buy a new phone every five years.