I guess I fail to see much value to it unless it is significantly cheaper than a backup generator. Also, if it's Lithium based, I'm not sure I want the thing in my garage. If that thing catches fire due to a overcharging or a manufacturing defect, you can kiss your house good bye.
Now if I can take an electric car to work and charge it up during the day for free and then use to spin my electric meter at home backwards at night, that sounds like something I would go for.
