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Question removable battery lithium

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.
my universal charger https://www.aliexpress.com/item/400...68#1000022185#1000066058#0_668#3422#15392#679
 

audioguru

Well-Known Member
Most Helpful Member
Talking and talking.
Are you talking about charging a Ni-MH battery? This battery is a completely different Lithium-Ion type.
It is charged with a constant current of about 0.5C (not 0.01C) until its voltage reaches 4.2V then it stays at 4.2V until it detects the charging current dropping to about 1/20th of its mAh rating. The voltage does not drop while charging. The voltage slowly drops when it is loaded as the charge is used up.

Many Lithium-ion batteries can be fast charged at 5C Many Lithium-ion batteries can discharged at 20C to 75C with no problems..
 

v4000ds

Member
I read some charging datasheet and it said that the controller waits before the voltage drops. If this does not happen, the battery is considered charged to the required voltage.
Charge impulse for 30 seconds, then a break and voltage measurement and so in a cycle.
 

audioguru

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Most Helpful Member
I read some charging datasheet and it said that the controller waits before the voltage drops. If this does not happen, the battery is considered charged to the required voltage.
Charge impulse for 30 seconds, then a break and voltage measurement and so in a cycle.
You should read about charging and discharging Lithium-Ion batteries at www.batteryuniversity.com and at semiconductor manufacturers of charger ICs for them. Here is their graph of charging:
 

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audioguru

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Sick people need medication, not batteries.
The batteries are 3V to 4.2V. 20V will explode them.
A multimeter must be switched to measure voltage, resistance or mA current.
The battery manufacturer knows what temperature sensor is on which extra terminal.
 

audioguru

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Most Helpful Member
The rotary switch on your multimeter is set to measure high voltage AC, not a low voltage DC battery.
 
with the digital multimeter scale 20 DCV I tested the batteries BM20 4.2v 2000mah and BP-5L 3.7v 1800mah and the result was BM20 4.14v and battery BP-5L the result was 4.09v but I didn't understand the BP-5L because it is 3.7 v, are these results good for long-term storage or not? What should I do? it's been 2 or 3 months since the last recharge and the universal charger LCD showed 75%
 

rjenkinsgb

Well-Known Member
Most Helpful Member
I repeat from some pages back:

Battery University explicitly says do NOT try to calculate state of charge from voltage as the mid charge voltage "slope" is too flat.
And:
What voltage? i know the BM20 has 4.2v and the BP-5L has 3.7v
WRONG.

Lithium cells have a "nominal" voltage of around 3.6 - 3.7V, which is the approximate average between full and empty.
The full charge voltage is around 4.2V

Different manufacturers call them different things; whatever they think looks better in advertising. The cells and voltage ranges are the same regardless.

-----------------

They are BOTH 4.2V fully charged; they are the same fundamental type of battery regardless of labelling.
But I repeat again you CANNOT properly gauge state of charge from voltage alone.

Though at over 4V, I'd say they are probably both far above the ideal storage range.
 
the result was 4.09v but I didn't understand the BP-5L because it is 3.7 v, are these results good for long-term storage or not? What should I do? it's been 2 or 3 months since the last recharge and the universal charger LCD showed 75%

what recommendation?
 

audioguru

Well-Known Member
Most Helpful Member
The BP-5L is a lithium-Ion with cobalt in it. It is 4.2V when fully charged. Many batteries that are 4.2V when fully charged are wrongly called 3.7V.
If it is a newer Lithium Ferrous Phosphate whatever (LiFeP04) then it is 3.6V fully charged.
 
I don't have the smartphone compatible with the BM20 battery so I'm discharging it through the universal charger but on the universal charger it shows 50% charge but when I go to measure the voltage with the multimeter it remains at 4.1v and I didn't understand it would be correct 50% shown on the display of the universal charger and on the digital multimeter will be shown something close to 3.8v and this does not occur

Is 3.8v voltage best for long term storage?
 

audioguru

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Most Helpful Member
Nobody knows what "50%" means on your cheap old charger. 4.1V is almost fully charged.
We nave been telling you on nearly 100 posts that a storage charge is when the voltage measures between 3.7V and 3.8V.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Nobody knows what "50%" means on your cheap old charger. 4.1V is almost fully charged.
We nave been telling you on nearly 100 posts that a storage charge is when the voltage measures between 3.7V and 3.8V.
I'm beginning to think he's just a troll, continually posting the same silly questions and ignoring all the answers?.
 
I'm not a troll I just realized today that the measurement of the % universal charger is different from the measurement V of the multimeter

can you tell me a good universal charger for these two batteries?
 

audioguru

Well-Known Member
Most Helpful Member
The batteries are designed to be charged by the charger circuit inside a phone.
Nobody uses an old and very cheap external charger like you do and since nobody does then nobody makes a better one.
 

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