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Know Li-ion battery Capacity

Hi ,
Can anyone help me to know the backup capacity of Lithium-ion battery by discharging process using balance charger?

Thanks

Hi @sudheeshk ,

I’m not sure I understand your question, can you please restate it? What do you mean by “backup capacity”?

-Adam

I believe he is trying to know the capacity of each battery. Generally as we do multiple charge - discharge cycles then the endurance of operations reduces as battery capacity reduces. Wanted to know standard methods to benchmark all the batteries to plan replacements etc…

Hi @sudheeshk and @kappa,

I see, understood. To determine the present capacity of the battery versus the original rated capacity, you should use the same method that Samsung uses to rate the cells. As far as I can gather from the datasheet, the method they use to rate the cells at 3000 mAh is as follows:

  • Charge to 4.20 +/-0.05 v @ 0.5C with a 100mA cutoff (CC-CV)
  • Discharge to 2.50 v @ 0.2C
  • Execute test at 23°C

Note that the ambient temperature and charge/discharge rate during the test can have a significant impact on the result, so the above method should be used for a totally accurate comparison.

There are some good graphs showing cycle life and how discharge rate affects usable capacity of the cells in the datasheet.

-Adam