Trying to charge battery

Thread Starter

Man10

Joined Jul 31, 2018
57
I was trying to charge a lithium ion cell. I used a lithium ion cell charger, that I bought from Walmart. The instruction booklet it came with, says it takes 8 hours to the charge the lithium ion cell. I have been charging the lithium ion cell for 2 days and it still won't reach 4.2 volts. What is wrong with this lithium ion cell? I sometimes measure the voltage. 1 time it was 3.91 volts, then I let it charge for hours, then it was 3.71 volts.
 

Thread Starter

Man10

Joined Jul 31, 2018
57
I have used the charger to charge other lithium ion cells, I don't think there is anything wrong with the charger.
 

Thread Starter

Man10

Joined Jul 31, 2018
57
I removed the lithium ion cell from a laptop, years ago, so I don't remember. The laptop was a Dell. The laptop battery contained six cell, in 2 rows.
 

Thread Starter

Man10

Joined Jul 31, 2018
57
Lithium ion battery run out of cycles? I read on Wikipedia if you charge and discharge a lithium ion battery, it has a maximum number of cycles.
 

Audioguru again

Joined Oct 21, 2019
2,982
A Lithium battery cell is 4.2V when fully charged and is ruined if it is less than 3V. Many chargers sense a voltage less than 3V then make a weak charging current. If the voltage does not rise then it quits and gives an error warning.

If a normal charging current is given to a battery with a voltage less than 3V then the chemistry inside the battery might prevent it from charging normally and cause it to explode and/or catch on fire. Also, its capacity is reduced.
A Lithium battery will produce many more charge-discharge cycles if it is charged to less than 4.2V and is discharged to more than 3V.

All my Lithium battery powered products shutdown before the voltage of a cell drops below 3V. They give a low batt warning at 3.2V.
 

Thread Starter

Man10

Joined Jul 31, 2018
57
I had other lithium ion batteries. I discharged them to below 3 volts, sometimes 2. Something, sometimes. As long as I don't discharge them to below 3 volts, they won't lose capacity or be ruined?
 

Audioguru again

Joined Oct 21, 2019
2,982
I had other lithium ion batteries. I discharged them to below 3 volts, sometimes 2. Something, sometimes. As long as I don't discharge them to below 3 volts, they won't lose capacity or be ruined?
If a Lithium battery is cheap then it quickly loses its capacity. Some are made with rice flour.
If a Lithium battery is xxx xxx. Please read about it at Batteryuniversity.
 
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