[lotsofmangos]

"I’ll say it another way: unless your solar-powered home is entirely disconnected from the grid, or your solar system is big enough to provide for all your electricity needs, an expensive battery backup system like Powerwall does not make economic sense.

No doubt battery technology is important for the management of the power grid of the future, but at this time the average homeowner should let the big power generation utilities take the risks and bear the costs of perfecting the technology."

cough .. http://en.wikipedia.org/wiki/Northeast_blackout_of_2003 .. cough