A 100kWh battery would run a 1kW bar heater (and nothing else) for 4 days. That's probably enough to heat one room and keep you alive, but it won't be giving you the full electric shower, cooking food, warm house and pipes not freezing experience. Even moreso if you want to keep some reserves in case it needs to last more days.
> "I'm not sure if anyone has done the math on what kinda timescale you are looking at for return on investment with a 100kWh battery"
A long one. 100kWh will cost you maybe $70,000 (e.g. 10x of these https://www.amazon.com/48-VDC-Kwh-Battery-Pack/dp/B079348MM1 ) (If it's not LiIon, but is lead-acid to be cheaper, you won't want to be using much more than 50% of it before it causes problems). At $1/kWh from the mains, about 8 years of mains electricity to buy it. At $0.25/kWh, 32 years.
What do you mean? In this scenario of 4 days heating per charge that makes 10k days which is 27 years, and that seems a reasonable sort of lifetime for a product - probably beyond any warranty period it has.
> "I'm not sure if anyone has done the math on what kinda timescale you are looking at for return on investment with a 100kWh battery"
A long one. 100kWh will cost you maybe $70,000 (e.g. 10x of these https://www.amazon.com/48-VDC-Kwh-Battery-Pack/dp/B079348MM1 ) (If it's not LiIon, but is lead-acid to be cheaper, you won't want to be using much more than 50% of it before it causes problems). At $1/kWh from the mains, about 8 years of mains electricity to buy it. At $0.25/kWh, 32 years.