Off-Grid Inverter

Updated 2026-08-24 · Read this page as Markdown

An inverter that creates its own AC network from a battery bank rather than following an existing grid, supplying loads in an installation with no utility connection. It is also called a standalone or battery-based inverter.

Unlike a grid-tied unit, an off-grid inverter must set the voltage and frequency itself and hold them steady while loads switch on and off, so surge capability matters as much as continuous rating — motors, pumps and compressors draw several times their running current at start-up. Sizing is driven by the largest simultaneous load rather than by the array. Because there is no grid to export to, the system needs a strategy for full batteries, which usually means shifting frequency to throttle any AC-coupled PV or diverting surplus to a dump load.

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Related terms

Hybrid Inverter A grid-tied inverter that also has a battery port and the control logic to charge and discharge storage, deciding moment by moment whether solar energy goes to the loads, to the battery or to the grid. Many hybrids can additionally supply a protected circuit during an outage. Inverter Type The architectural class of the unit: string inverter, microinverter, hybrid or off-grid. The type determines where it sits in the system, what it can be connected to, and whether it can work without a grid present. Microinverter A small inverter mounted behind an individual solar module that converts that module's DC output directly to grid-frequency AC. Modules are then connected in parallel on an AC trunk cable instead of being wired into a DC string. Number of Phases Whether the inverter delivers single-phase or three-phase alternating current on its output. It must match the building's supply, and above a certain power level the network operator normally requires three-phase connection. Transformerless Inverter An inverter that converts DC to AC without a galvanic isolation transformer between the array and the grid. Removing the transformer raises efficiency and cuts weight and size, and it is the dominant design in modern residential equipment.

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