What does 'whole home backup' actually mean?
Whole home backup means that when the electricity grid fails, your battery storage system continues to power your entire home — every circuit, every socket, every appliance — from stored energy, without any manual intervention required.
This is distinct from partial or 'critical circuit' backup, where only selected circuits (for example, the fridge, router and some lighting) are protected. Whole home backup requires a correctly sized battery, a compatible hybrid inverter, and an installation configured to provide it.
The term is sometimes used loosely in marketing. This guide explains how backup actually works, what equipment supports it, and what realistic expectations look like — because understanding the difference between a genuine whole-home backup system and a basic EPS setup can save you from a frustrating experience during a power cut.
How Emergency Power Supply (EPS) mode works
Emergency Power Supply (EPS) mode is the technical name for what most battery systems provide during a grid outage. When the hybrid inverter detects that grid power has been lost, it disconnects from the grid (to protect any engineers working on the line from back-feed) and switches to island mode — powering your home solely from the battery.
On modern hybrid inverters — including EcoFlow, Sigenergy and SolaX — this switchover takes between 10 and 20 milliseconds. Most consumer electronics, LED lighting and motors will not notice an interruption of this duration. However, some sensitive equipment may still be affected.
If solar panels are generating at the time of the outage, they continue to contribute to powering your home and recharging the battery. This is particularly valuable during summer daylight power cuts, where you may be able to run indefinitely as long as generation exceeds consumption.
When grid power is restored, the inverter automatically reconnects and resumes normal operation. No manual reset is required on any of the systems we install.
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