Battery Capacity Calculator
· Battery capacity formula. As you might remember from our article on Ohm's law, the power P of an electrical device is equal to voltage V multiplied by current I:. P = V * I. As energy E is power P multiplied by time T, all we have to do to find the energy stored in a battery is to multiply both sides of the equation by time:. E = V * I * T. Hopefully, you remember that amp hours are a measure ...