Battery reserve

Also known as Backup reserve, Reserve level, Minimum SoC

Battery reserve is the part of a battery's state of charge that a system keeps back from ordinary discharge, usually for backup readiness or battery protection.

Battery reserve is a configured or manufacturer-managed minimum state of charge that keeps some stored energy unavailable for everyday self-consumption, EV charging or tariff discharge. In a home battery app it may appear as a reserve slider, backup reserve or minimum SoC value. Some systems use the reserve to hold energy for backup power, while others also use minimum state-of-charge and recovery behaviour to protect the battery. A reserve is not the same as guaranteed outage runtime: backup still depends on the installed backup or EPS hardware, isolated circuits, inverter output, battery state of charge and the loads connected at the time.