From HeatSpring.com PV Boot Camp
I never realized how complex a battery system could be. Although it sounds like a really cool idea to have a battery backup system on your house for when the grid goes down, for the amount of time the grid is actually down it seems a lot more cost efficient to have a gas generator.
And not that bad of an idea to take the day off from having electricity.
I lived in a cabin in Alaska without electricity. It was fun.
You can make an argument that a gas generator is often better for the environment than a lead-acid battery bank for a back-up system that is rarely used. Just the amount of gas used driving around installing the battery system might be more than the generator uses. It is nice though not having to depend on gas in case of the apocalypse.