A home battery is supposed to keep your essential circuits running when the grid goes down. When it doesn't, the cause isn't always a dead battery. Here are the five things we check first.
First, the backup reserve setting. Many batteries are configured to discharge every evening to offset peak rates, which can leave little reserve for an outage. Raising the backup reserve in the app is often the fix.
Second, what's actually backed up. Some systems only back up a subpanel of essential loads. If the circuit you expected to stay on isn't wired to that panel, the battery is working as designed, just not as you expected.
Third, the gateway or transfer switch. The battery can be fine while the device that disconnects your home from the grid fails to switch over. Fourth, communication: a battery that has lost its connection to the gateway or inverter may not respond during an outage.
Fifth, the battery itself. Batteries degrade over time, and modules can fail. A diagnostic tests the battery's state of health along with the gateway and inverter, so you know whether you need a setting change, a component repair, or a replacement, and whether the manufacturer's warranty covers it.