You probably need to think in multiples of battery given the real serious nature of keeping power going for your Dad.
From Wiley: If you're hitting them after they drop, that's not defense, that is revenge.
Just pulled the trigger on it and about to get my whole roof done. Anything I should expect?
If you add several Tesla wall batteries, you'll find that your electricity costs will pay for itself in about 5 years. Were you able to secure any government grants?