If we imagine a simple circuit with a battery and a capacitor with negligible internal resistance, the capacitor is charged up to a point where the voltage it stores is equal to the voltage of the battery. The battery has supplied an energy equal to V*I*T (voltage times current times time). However the capacitor now has a stored energy of ½*Q*V. The battery has supplied Q*V joules of energy but the capacitor is storing only ½ of that amount. How is this possible? I know it can’t be resistance as it always a half difference in energy between the battery and the capacitor and resistance would have a varying affect depending on the circuit. Also the problem still occurs when the circuit has no resistance. I’m wondering if my A-Level studies don’t explain in enough detail the theory about capacitors and that’s why I’m not understanding this. Would appreciate any feasible explanations.