Yes. Battery only is a normal path here, not an exception we make — and for most people without panels the outage is the reason rather than the bill. When the grid drops, the battery carries your whole main panel, the way a generator would without the fuel, the noise or the service visits. Duration is the variable, not scope: it runs until the stored energy is gone, which is what we size on the call. The bill changes too. Without panels nothing exports, so there is no buyback line: your power comes at $0.129 a kWh all-in — energy and delivery in one number — and the Solrite agreement is $20 a month on its own invoice. One thing to be clear about, because it is the usual misunderstanding: the battery does not reduce the kWh you buy. Every kWh still goes through the meter, just at a different rate. The calculator has a battery-only mode if you want your own numbers before the call.