Tesla popularized the concept of batteries in the home. Ford connected the home to the truck.
The funding round pops the startup's valuation to $2 billion, big money in the solar software space.
CEO Arch Rao says the device's shrinking size and price can help put battery, EV and appliance controls into more homes and apartments — and open up more utility partnerships.
"The industry will evolve from rack-mounted to building-integrated PV."