How to verify the Energy and Capacity delivered by the Lithium Ion battery? I have a Lithium ion batter with below configuration: Nominal Voltage 4.2 V Nominal capacity 2250 mAh I am calculating the energy and capacity every second for my experiments. I use below formula to calculate the energy and capacity calculation: consider initial V= 4v and constant current I= 5A E = P * t --> E-energy,P-Power,t-time in hour eg: E= 20 * (1/3600) = 0.005 C = (E * 1000)/V --> C-capacity, V-voltage Eg: C = (0.005 *1000)/4 = 1.25 mAh I have discharged the battery from 4.1V to 2.5V I added the energy and capacity from every second. Total accumulated Energy I got was around 7 wh and capacity is around 2500 mAh Capacity which i got was more than the rated capacity. I really dont know where i did the mistake or this was expected. A small help,will be highly appreciated. Thank you.