The requirement is to compute the capacity of the battery in order to calculate the capacity degradation.
The input which can be acquired are current, voltage, relative time, battery level (in terms of percentage).
As per as formula
Capacity = Integral of Current over time. (of discharge cycle)
So the doubt is, does the time here mean from reaching, say, x voltage to y, or from battery level 100% to 0% on discharging?
Basically, how is the interval to calculate capacity is considered?