How is the state of charge of a nickel-cadmium battery determined?

The state of charge (SoC) of a nickel-cadmium (NiCd) battery is typically determined by measuring its open-circuit voltage (OCV) after a resting period, as the voltage correlates with the charge level. Additionally, a discharge curve can be used, where the voltage is monitored during discharge to estimate the remaining capacity. Another method involves using a specific gravity meter to measure the electrolyte density, but this is less common. Overall, OCV measurements are the most practical approach for determining SoC in NiCd batteries.