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Question removable battery lithium

v4000ds

Member
In my region (Ukraine) in summer in August there are temperatures as high as 32 ... 42 degrees. The phone in black pants heats up to 60+ degrees and turns off.
But if I wear white pants, it doesn't happen very often. It is best to hold the phone in your hands, then it will not heat up above 50 (otherwise you will get burned).
I think that such a problem is not only in hot regions.
Probably, there are smartphones in Africa, they somehow solve this problem. Maybe some special batteries. Is it really possible to carry them in the refrigerator?
 

rjenkinsgb

Well-Known Member
Most Helpful Member
the temperature in my region varies between 31-34ºC and I am looking for the best option for my conditions and charging at 50 or 75% has self-discharge etc.
All you can do with what you have is try and aim for around half charge, and store them the coolest place practical - eg. somewhere shaded rather that a place that gets direct heat from the sun during the day.

Check them every few months if you are not using them, and bring back to around 50% if they have gone below eg. 30%
 
For my temperature and conditions is 50% safer than 75% for long term storage? i'm going to use this chinese charger from the link i posted but it shows the actual 50% value on the lcd?

What is the easiest way for me to reduce their load from 75% to 50%?

BM20 xiaomi and BP-5L batteries

How many months on 50% storage do these batteries maintain a good and safe charge? how long for a new charge?
 

audioguru

Well-Known Member
Most Helpful Member
Name-brand batteries hold a storage charge for a long time. Your batteries are not Name-Brand so just guess how soon they will fail.
 

audioguru

Well-Known Member
Most Helpful Member
Don't you think that some cheap junk will be awful but other cheap junk might be a little better than terrible?
 

v4000ds

Member
Non-branded batteries are made of poor quality materials and may create an internal short circuit
50% or 75% or 25%, 0% can also explode
For my temperature and conditions is 50% safer than 75% for long term storage?
The lower the initial temperature before the short circuit, the lower it will be after. For example, your battery is capable of heating itself up to 40 degrees in a short time during a short circuit. If its initial temperature was 60 degrees (which is not recommended), then its final temperature will be 60 + 40 = 100 degrees. At this temperature, the electrolyte boils and it is guaranteed to explode.
Also, temperatures above 40-60 degrees can damage the separator and from this the short circuit will intensify even more, a chain reaction will begin.
But until you start using them (discharging), they are unlikely to heat up above 40-60 degrees.
Their charge (50%, 75%) determines how much they heat up after a short circuit.
How many months on 50% storage do these batteries maintain a good and safe charge?
My laptop dell battery discharge from 99% to 0% after a couple of months, but under the sticker, the voltage on each pair is 3.6 ... 3.8 volts.
I think it's safe for 1 month
 
is there any test to find out if the battery has been affected in its useful life because of storing at 75% or charging? test to find out if the battery is 100% and after that I store at 50% with care for long life
 

audioguru

Well-Known Member
Most Helpful Member
Connect a load, calculate the average current, then time when the battery voltage has dropped to 3.0V. Then simply calculate the mAh and compare it to the rated mAh.
 
For both batteries it is best for long term storage to charge to 3.6V???

why the batteries have different voltages 3.7 or 4.2v and you say they all have a single voltage of 100%?

store in voltage of 3.6v (50%) the self-discharge is slower and after how many months do I need to recharge so that it doesn't go below 3.0v?
 

audioguru

Well-Known Member
Most Helpful Member
You have already been told that Name-Brand batteries are high quality and no-name-brand batteries like you have are cheap junk.
High quality batteries hold a storage voltage for a long time, mine for 20 years. Junk batteries need you to guess about them.

I store my Lithium batteries at 3.7V but I have been told it is too low and to use 3.8V.
 
my batteries are unknown so i need to figure out the best storage voltage and charging intervals in the worst case

3.6v, 3.7v, 3.8v are best for long term storage?
 

v4000ds

Member
What is the voltage of a fully charged battery, volts?
There are different lithium batteries.

For lithium-cobalt, which produce 4.2 volts, 3.7 ... 3.8 volts are optimal.
In short, you charge them up to 3.8 and put them on the shelf. Wait until they are discharged to 3.7 and charge again.
 
between 3.5v and 3.8v is the best for long term storage for these two mentioned batteries?

please guide me the scale to test with multimeter if it is among these good loads for storage
 

v4000ds

Member
I dont know. No one knows. Except for God.
It is not advisable to discharge to 3.5, you must keep 3.6. 3.6 is the nominal voltage. So the battery is bought in the store.
3.6 minimum, 3.8 maximum

It is difficult to charge the battery unless the voltage is raised 0.1 volts (for example) above the current voltage. Immediately after the start of the supply, the battery has such a voltage. After some time, the voltage decreases again to the previous one.
When the voltage stops decreasing, the battery is considered charged to that voltage.

But the "trick" is that the higher the charge current, the longer it takes for the voltage to drop. If the battery is charged with a current of more than "C recommended" (0.1 C and less, 8 hours), it may take so long that the charger will not be able to detect it and will consider it charged. After a couple of days, the battery will discharge to its initial voltage. For example, there will be 3.6 volts.

To avoid this, it must be charged with a current of 0.1C or less, regardless of its internal resistance. After disconnecting (!) from the charger, its voltage should be desired. For example, 3.8 volts. This voltage should not drop quickly. Measure it after several (2-5) days. If it is initial (for example 3.6 volts), then it is necessary to reduce the charge current by 2 times. If at a charge current of 0.01 C (for example, 20 milliamperes with a capacity of 2000 milliampere hours), the voltage drops after several (2-5) days (or less) to initial 3.6 volts and below, you need to discard the battery and buy a new battery.
0.01 C is used by manufacturers to indicate (mark) the maximum capacity. Charging with 0.01C and discharging with the same current, guarantee the maximum capacity.

This is not suitable for practical use, but may be suitable for storage.
 

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