What is a battery power conversion system, or PCS?

A power conversion system (PCS) connects a battery's direct-current electricity with the site's alternating-current circuits, converting in both directions for charging and discharge [S1]. An assumed 100 kW PCS supplying a constant 100 kW load from 200 kWh gives two hours before losses or reserves. Check continuous output and coupling separately from storage capacity. Checked October 2026.

Last checked 19 October 2026

What does a power conversion system mean for your site?

A power conversion system (PCS) is the bidirectional power-conversion equipment between a battery and alternating-current circuits [S1]. Why it matters for your site: enough stored energy does not establish that the system can deliver the power your equipment needs at the same moment.

Batteries use direct current (DC). Your site’s AC circuits use alternating current. The PCS converts AC to DC for charging, then DC to AC when supplying the building or grid [S1]. Its scope can include inverter modules, controls and protection, rather than a single conversion board [S2].

Which battery and PCS ratings should you check?

Request continuous charge and discharge power, any temporary peak rating and its duration, plus the measurement boundary. Ask whether figures describe the battery side or the AC connection. Keep the battery’s energy capacity separate from the converter specification.

An illustration, not a quote: assume 200 kilowatt-hours (kWh) of usable energy and continuous output of 100 kilowatts (kW). kWh measures energy; kW measures power. Ideal duration = 200 ÷ 100 = 2 hours. Losses and reserves are excluded; the inputs are assumptions. This does not establish performance at your premises.

How does PCS relate to AC and DC coupling?

In an AC-coupled layout, the battery has a conversion path connected to the site’s AC circuits. A DC-coupled solar-and-battery arrangement can share the solar inverter. The laboratory’s modelling illustrates how these paths change where energy passes through conversion equipment [S3].

Use AC versus DC battery retrofits for the layout decision and how a business battery works for the other components. Request a diagram showing simultaneous solar output and battery discharge limits before accepting a proposal.

Next step

Use cut energy costs and the site check to prepare your brief, then get matched with an installer that covers your area.

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