A method of balancing voltages in a group of capacitors (6; 12A-12D) of an electronic device, comprising: determining a characteristic value associated to a selected one of the capacitors making a balancing determination regarding whether to (i) inject energy into the selected one of the capacitors from an energy storage element, or (ii) extract energy from the selected one of the capacitors into the energy storage element based on the characteristic value, wherein the balancing determination determines (i) to inject energy into the selected one of the capacitors from the energy storage element if the determined characteristic value is greater than zero plus a positive hysteresis voltage, or (ii) to extract energy from the selected one of the capacitors into the energy storage element if the determined characteristic value is less than zero minus a negative hysteresis voltage; and either injecting energy into the selected one of the capacitors from the energy storage element, or extracting energy from the selected one of the capacitors into the energy storage element based on the balancing determination; characterized in that: the characteristic value associated to the selected capacitor is a voltage spatial second derivative of the selected capacitor, determined using the voltage of the selected one of the capacitors, the voltage of a first remaining one of the capacitors and the voltage of a second one of the remaining capacitors; and in that the method further comprises: determining a level of current in the energy storage element; applying a DC voltage from any combination of the capacitors to the energy storage element to discharge the energy storage element if the level of current in the energy storage element is above a predetermined first threshold amount; and applying a voltage from any combination of the capacitors to the energy storage element to charge the energy storage element if the level of current in the energy storage element is below a predetermined second threshold amount. determining a characteristic value associated to a selected one of the capacitors making a balancing determination regarding whether to (i) inject energy into the selected one of the capacitors from an energy storage element, or (ii) extract energy from the selected one of the capacitors into the energy storage element based on the characteristic value, wherein the balancing determination determines (i) to inject energy into the selected one of the capacitors from the energy storage element if the determined characteristic value is greater than zero plus a positive hysteresis voltage, or (ii) to extract energy from the selected one of the capacitors into the energy storage element if the determined characteristic value is less than zero minus a negative hysteresis voltage; and either injecting energy into the selected one of the capacitors from the energy storage element, or extracting energy from the selected one of the capacitors into the energy storage element based on the balancing determination; characterized in that: the characteristic value associated to the selected capacitor is a voltage spatial second derivative of the selected capacitor, determined using the voltage of the selected one of the capacitors, the voltage of a first remaining one of the capacitors and the voltage of a second one of the remaining capacitors; and in that the method further comprises: determining a level of current in the energy storage element; applying a DC voltage from any combination of the capacitors to the energy storage element to discharge the energy storage element if the level of current in the energy storage element is above a predetermined first threshold amount; and applying a voltage from any combination of the capacitors to the energy storage element to charge the energy storage element if the level of current in the energy storage element is below a predetermined second threshold amount. the characteristic value associated to the selected capacitor is a voltage spatial second derivative of the selected capacitor, determined using the voltage of the selected one of the capacitors, the voltage of a first remaining one of the capacitors and the voltage of a second one of the remaining capacitors; and in that the method further comprises: determining a level of current in the energy storage element; applying a DC voltage from any combination of the capacitors to the energy storage element to discharge the energy storage element if the level of current in the energy storage element is above a predetermined first threshold amount; and applying a voltage from any combination of the capacitors to the energy storage element to charge the energy storage element if the level of current in the energy storage element is below a predetermined second threshold amount. determining a level of current in the energy storage element; applying a DC voltage from any combination of the capacitors to the energy storage element to discharge the energy storage element if the level of current in the energy storage element is above a predetermined first threshold amount; and applying a voltage from any combination of the capacitors to the energy storage element to charge the energy storage element if the level of current in the energy storage element is below a predetermined second threshold amount.