Question

A lithium-ion battery for a mobile phone has a self discharge rate of 4% per month. What would be discharged after one month for a battery rated at 1.8 V and 500 mAh?

Answer 1

All batteries are affected by self discharge. It is a characteristic of a battery and is not a manufacturing defect. Self discharge is permanent, is dependent on type of battery, its chemistry, manufacturing process, maintenance while in use and age. Self discharge cannot be reversed

A secondary battery which is rated with a self discharge rate of `4%` per month, means that after a period of one month has elapsed the balance shelf `mAh` of a fully charged battery would be `96%` of the rated value. i.e., it would be `500xx0.96=480\ mAh`.

It should also be remembered that the rated maximum value of voltage will also drop. The value of remaining voltage is dependent on manufacturer to manufacturer.

Rechargeable battery average self discharge rate per month comparison chart