= Battery capacity
{title2=$Q=\int I\,dt$}
<Battery capacity> is the amount of <electric charge> delivered between specified charged and discharged states under stated conditions. It is $Q=\int I(t)\,dt$, commonly reported in ampere-hours; $1\,\mathrm{Ah}=3600\,\mathrm C$.
Capacity is distinct from delivered <energy>, which is $\int V(t)I(t)\,dt$. Two batteries with equal ampere-hour ratings can deliver different <energies> because their voltages differ. Discharge rate, <temperature>, endpoint voltage and aging affect the measured capacity. Comparing ratings therefore requires the same test conditions and a stated choice of active-material or full-device <mass> when using <specific capacity>.
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