State of Charge (SOC) represents the remaining battery capacity as a percentage of its rated capacity. An SOC of 0% means the battery is fully discharged, while an SOC of 100% means it. SOC refers to the percentage of a solar battery's usable capacity that is currently available, helping users understand what SOC means in a solar system and how much stored solar energy can be used. Whether you are a solar system owner or considering a solar solution, knowing how SOC impacts your. Battery capacity is one of the key performance indicators of a battery, indicating the amount of electricity a battery can deliver under certain conditions (discharge rate, temperature, terminal voltage), usually measured in ampere-hours (Ah). SOC is not directly measurable; it must be estimated using voltage, current, temperature, and algorithms inside the BMS. Full Charge Capacity (FCC) and State of Health (SOH) strongly affect SOC. If you work in the lithium-ion battery space—whether in EVs, energy storage, or consumer electronics—you've likely come across SOE (State of Energy) and SOC (State of Charge). Whether you're looking at your phone's battery icon, an electric vehicle.