Does a 12V battery necessarily have twice the stored electrical potential energy that a 6V battery has?
A battery is made up of cells. Each cell has the same voltage, and in the same battery, the same ampere-hour capacity. A six volt battery has three cells, and a 12V battery 6 cells (lead acid battery). The capacity of a cell or battery is related to its size. It is measured by how many amps can be supplied for how many hours. The voltage of a cell is always the same for the same type of battery. If two identical 6V batteries are connected in series it forms a 12V battery, with twice the voltage and the same capacity in ampere hours as one battery. In parallel, it is still 6V, but twice the capacity in ampere hours. Power is volts x amps, and is measured in watts. Energy takes into account how long the power is used, so is watts x hours, and is named watt-hours. Battery capacity is usually rated in ampere hours, but knowing the voltage it is easy to convert to watt-hours = ampere-hours x volts. As the voltage varies considerably over the discharge cycle, the watt hour figure can be misl
