Spatial and temporal variability of PV generation is a challenge for secure operation of the power systems. Several solutions are already proposed to deal with this issue. Among the proposed solutions, storage technologies (particularly battery) attracted more attention as a promising solution for the application in medium-and large-scale PV plants. While numerous research studies addressed optimal sizing and real-time operation of the storage systems in such applications, there is no study on the battery operation assessment in real-world application based on field data. In this paper, one year of experimental data from a 3.275 MWp PV plant with 600 kW/760 kWh Li-Polymer battery system is examined from different perspectives (e.g., battery energy, power, rate of change of power (RoCoP), and state-of-charge (SOC)) to draw insights from battery operation within the plant. The field data inherently contains system-wide losses, smoothing effect of the PV plant, and PV inverter operation for reactive power control, which provides a realistic assessment. Furthermore, several operational parameters (such as energy and power during ramp events) are evaluated and modelled using appropriate statistical tools based on experimental data. In addition, a simple super-capacitor sizing study is carried out to reveal the effectiveness of a hybrid energy solution for such applications. Observations and insights drawn from the proposed analyses will help future research on the battery sizing and operation to effectively account for real-world characteristics and requirements.