The starting point

A battery alone does not establish that a home will have backup power. The proposed system must specify compatible equipment, the circuits supplied and how it operates during an outage.

Start with the loads

Make a short list of what matters during a power cut: lighting, communications, refrigeration, heating controls or other equipment. Record which loads must run together.

This list gives the installer something concrete to design around. Whole-home coverage still needs a discussion about simultaneous demand and available power.

Separate power from duration

Output power determines which combinations of loads can be supplied. Available energy determines how long the selected demand can be sustained. Neither question is answered by the battery’s marketing name.

A runtime estimate should state the starting charge, reserve, losses and assumed load. Solar recharge should be a separate scenario, not an assumption that every outage is sunny.

Ask for a documented design

Request the proposed backup coverage and handover instructions in writing. Discuss what happens if the internet is unavailable and how normal operation resumes.

  • Which circuits are backed up?
  • Which loads must be limited or disconnected?
  • What has been tested at commissioning?