PCS
PCS (power conversion system) is a storage system's battery inverter. Its rating in kW sets how much power the system can charge or discharge at once.
What does PCS mean?
The Power Conversion System is the storage system’s battery inverter: it converts alternating current to direct current when charging, and back when discharging. Its rated power in kW determines how much the system can absorb or deliver at once — regardless of how large the battery is.
The PCS also defines the system’s grid quality: harmonic distortion, power factor and behaviour during grid faults are PCS properties. In systems with a backup function, the PCS forms the local grid during island operation.
What matters in practice
- the PCS power must cover the highest load peak to be shaved
- distinguish continuous power from short-term overload capability
- island-mode capability is a PCS property, not a battery property
- with DC blocks (e.g. PotisBank L3.7/L5.0), the PCS is planned separately
Practical example
A business wants to shave 80 kW peaks. A 200 kWh system with a 50 kW PCS cannot do it — the peak passes the PCS limit and flows from the grid. The same battery with a 105 kW PCS solves the task.
The Speichercampus perspective
During the project review, Speichercampus matches PCS power against the load profile. The power question comes before the capacity question — an undersized PCS makes even the largest battery useless.