In my home, a single Powerwall battery could cover 90+ percent (or perhaps 95+ percent?) of nights even in an off-grid arrangement. Covering the rare extremes w

In my home, a single Powerwall battery could cover 90+ percent (or perhaps 95+ percent?) of nights even in an off-grid arrangement. Covering the rare extremes with a $150 generator would be more cost-efficient than using a larger battery, and likewise, covering the usual case with a battery would be more cost-efficient than running all nights inefficiently using our $5/USgal gasoline.