I have a Bluetti Ac200 Max ( 2200 watt sine wave invertor) and 2 B230 extension batteries, giving me a total capacity of 6.1 KWH. I use this to back up my essential circuits in my house via a generator transfer panel. It wont run any 240 volt items, but during a recent 39 hour power outage in my neighborhood because of an historical rainfall event, I was able to keep my propane fired combi boiler ( domestic hot water and heat ( if needed)) , refrigerator, kitchen lights and outlets, internet, tv running. I can get approx 30 hours running time out of it and then i can use my small Honda invertor generator to recharge in approx 5-6 hours while simultaneously using it. So essential i can get 60 hours of back up power - system is precharged from the grid prior to outage and the 1 gallon of gas the Honda generator would use to recharge it at the 30 hour mark. It certainly proved its worth during the outage.