| > I would like to use my car battery as a temporary home battery in the inevitable case of a grid outage. This opens the option to bring energy home from another location. Reduce or eliminates the need for a battery in a grid-tied house. Question is "how long?" and "how much?" Lets take a 100 kWh battery which matches a Tesla Model S battery option and is a nice number for doing conversions from. https://shrinkthatfootprint.com/average-household-electricit... > The recent figures, as of 2021, show that the average annual electricity consumption for a U.S. residential utility customer is 10,632 kilowatthours (kWh). If you divide that by 12 months, the average monthly electricity consumption is 886 kWh per month. What about in a single day? That would be 10,715 KWh divided by 365, or 29 kWh. Then the average daily electricity consumption is 29 kWh. So, hypothetically, 100 kWh would give you 3 and almost 4 days. This can be improved by unplugging things that consume more power. The other part with this is a "once that 100 kWh is drained, you're stuck stuck." You're going to still need something between the mains power and the circuit breaker box. I'm also going to note I don't know what rate it can discharge. You might also want to look at a system that is a dedicated whole house battery backup ( https://www.zdnet.com/home-and-office/energy/best-home-batte... ) The zdnet article links to a Lowes worksheet - https://www.lowes.com/pdf/portable_generator_wattage_chart.p... And from that, look at the "this is what we want" and the question of "generator or battery" becomes interesting. Then consider also, you can get a 10,000 watt generator (that does a cutover in event of a power outage in 7 seconds) for about $3000 which can provide 10 kW at 40 amps. |