Get more than 100% capacity from a cell?

Posted on Posted in USEFUL DOCS

Get more than 100% capacity from a cell?

Generally, the capacity comes out from a battery(discharge capacity) will be less than the capacity comes into a battery(charge capacity).

But for some customers, when they perform charge and discharge operation with Neware BTS software at the beginning, it’s strange to see the discharge capacity is more than the charge capacity.

How’s that? There are 2 possible reasons.

1. It happens in the 1st charge-discharge cycle

The capacity output percentage is calculated with the equation output capacity(discharge)/input capacity(charge), for the 1st cycle, the battery usually charged from 30% or even more leftover capacity.
For example, normally there’s be 25%-60% capacity of a battery, when it’s charged to full, the charged capacity recorded by software is about 40%-75%.
When it’s 100% discharged, it gives you the impressions the discharge capaticy is more than the charge capacity.
But look at the data from the 2nd complete(charge-discharge) cycle, the output percentage will be less than 100%.

2. Due to the improper test steps

If this happens in the middle cycles instead of the 1st cycle, it’s very possible due to the improper test steps.
Such as using very low current to charge battery but using very high current to discharge battery and the cut-off voltage wasn’t correctly set up.

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