Storage and outage backup are different requirements
A grid-connected battery may be designed mainly for self-consumption or time-of-use savings. To operate during a grid outage, the system must safely isolate from the utility and create a supported local electrical island. That requires the right inverter, controls and transfer/isolation hardware.
Before approving a backup design
- Ask what is backed up: the whole panel, a dedicated critical-load panel, or selected circuits.
- Check continuous and surge power: motors, pumps, air-conditioning and compressors can demand much more power at startup.
- Confirm phase support: single- and three-phase properties can require different hardware and load planning.
- Identify the isolation/transfer device: for example, supported SolarEdge systems may use the Home Backup Interface.
- Set a backup reserve: a battery used aggressively for tariff arbitrage may have little energy left when an outage starts unless a reserve is configured.
- Test commissioning: the installer should verify safe transfer and the intended backed-up loads under the manufacturer’s commissioning process and local electrical rules.
Quote requirement
Ask the installer to write down the expected backup kW, usable backup kWh, which circuits are included, any loads that must be manually managed, and the assumptions used for outage runtime.