State of chargeState of charge (SoC) is the level of charge of an electric battery relative to its capacity. SoC is usually expressed as percentage (0% = empty; 100% = full). An alternative form of the same measure is the depth of discharge (DoD), calculated as 100 - SoC (100% = empty; 0% = full). SoC is normally used when discussing the current state of a battery in use, while DoD is most often seen when discussing the lifetime of the battery after repeated use. In a battery electric vehicle (BEV), SoC for the battery pack is the equivalent of a fuel gauge.
